Fixed popups not having a shadow [windows].

Fixed content being misplaced after window is restored into maximized position [windows].

core/src/main/java/com/github/weisj/darklaf/platform/DecorationsHandler.java

@@ -79,7 +79,7 @@ public class DecorationsHandler {
     }
 
     public void installPopupWindow(final Window window) {
-        decorationsProvider.installPopupMenu(window);
+        decorationsProvider.installPopupWindow(window);
     }
 
     public void uninstallPopupWindow(final Window window) {
@@ -108,4 +108,12 @@ public class DecorationsHandler {
     public void setDecorationsEnabled(final boolean enabled) {
         decorationsEnabled = enabled;
     }
+
+    public void adjustContentArea(final JRootPane root, final Rectangle rect) {
+        decorationsProvider.adjustContentArea(root, rect);
+    }
+
+    public void adjustWindowInsets(final Window window, final Insets i) {
+        decorationsProvider.adjustWindowInsets(window, i);
+    }
 }

core/src/main/java/com/github/weisj/darklaf/platform/DefaultDecorationsProvider.java

@@ -41,11 +41,6 @@ public class DefaultDecorationsProvider implements DecorationsProvider {
 
             @Override
             public void uninstall() {}
-
-            @Override
-            public Insets getWindowSizeAdjustment() {
-                return new Insets(0, 0, 0, 0);
-            }
         };
     }
 

core/src/main/java/com/github/weisj/darklaf/ui/DarkPopupFactory.java

@@ -81,7 +81,6 @@ public class DarkPopupFactory extends PopupFactory {
                                      && Boolean.TRUE.equals(((JComponent) contents).getClientProperty(KEY_NO_DECORATION)));
             boolean opaque = isJComponent
                              && Boolean.TRUE.equals(((JComponent) contents).getClientProperty(KEY_OPAQUE));
-            window.setBackground(PaintUtil.TRANSPARENT_COLOR);
             if (window instanceof RootPaneContainer) {
                 JRootPane rootPane = ((RootPaneContainer) window).getRootPane();
                 if (opaque) {

core/src/main/java/com/github/weisj/darklaf/ui/progressbar/DarkProgressBarUI.java

@@ -104,7 +104,7 @@ public class DarkProgressBarUI extends BasicProgressBarUI implements PropertyCha
             }
 
             Insets i = progressBar.getInsets();
-            DarkUIUtil.removeInsets(r, i);
+            DarkUIUtil.applyInsets(r, i);
             int orientation = progressBar.getOrientation();
 
             Color startColor, endColor;
@@ -248,7 +248,7 @@ public class DarkProgressBarUI extends BasicProgressBarUI implements PropertyCha
             }
 
             Insets i = progressBar.getInsets();
-            DarkUIUtil.removeInsets(r, i);
+            DarkUIUtil.applyInsets(r, i);
             int amountFull = getAmountFull(i, r.width, r.height);
 
             Shape fullShape, coloredShape;

core/src/main/java/com/github/weisj/darklaf/ui/rootpane/DarkSubstanceRootLayout.java

@@ -28,7 +28,9 @@ import java.awt.*;
 
 import javax.swing.*;
 
+import com.github.weisj.darklaf.platform.DecorationsHandler;
 import com.github.weisj.darklaf.platform.decorations.CustomTitlePane;
+import com.github.weisj.darklaf.util.DarkUIUtil;
 
 /**
  * @author Konstantin Bulenkov
@@ -53,17 +55,10 @@ class DarkSubstanceRootLayout implements LayoutManager2 {
         int tpWidth = 0;
         int tpHeight = 0;
         Insets i = parent.getInsets();
-
+        DecorationsHandler.getSharedInstance().adjustWindowInsets(DarkUIUtil.getWindow(parent), i);
-        Insets sizeAdjustment = new Insets(0, 0, 0, 0);
-        CustomTitlePane titlePane = getTitlePane(SwingUtilities.getRootPane(parent));
-        if (titlePane != null) {
-            sizeAdjustment = titlePane.getWindowSizeAdjustment();
-        }
-
-        i.set(i.top + sizeAdjustment.top, i.left + sizeAdjustment.left,
-              i.bottom + sizeAdjustment.bottom, i.right + sizeAdjustment.right);
 
         JRootPane root = (JRootPane) parent;
+        CustomTitlePane titlePane = getTitlePane(root);
 
         if (root.getContentPane() != null) {
             cpd = root.getContentPane().getPreferredSize();
@@ -125,8 +120,7 @@ class DarkSubstanceRootLayout implements LayoutManager2 {
         }
         if ((root.getWindowDecorationStyle() != JRootPane.NONE)
             && (root.getUI() instanceof DarkRootPaneUI)) {
-            JComponent titlePane = ((DarkRootPaneUI) root.getUI())
+            JComponent titlePane = ((DarkRootPaneUI) root.getUI()).getTitlePane();
-                                                                  .getTitlePane();
             if (titlePane != null) {
                 tpd = titlePane.getMinimumSize();
                 if (tpd != null) {
@@ -152,34 +146,42 @@ class DarkSubstanceRootLayout implements LayoutManager2 {
     public void layoutContainer(final Container parent) {
         JRootPane root = (JRootPane) parent;
         Rectangle b = root.getBounds();
+
         Insets i = root.getInsets();
-        int nextY = 0;
+
-        int w = b.width - i.right - i.left;
+        b.setLocation(0, 0);
-        int h = b.height - i.top - i.bottom;
+        DarkUIUtil.applyInsets(b, i);
 
         if (root.getLayeredPane() != null) {
-            root.getLayeredPane().setBounds(i.left, i.top, w, h);
+            root.getLayeredPane().setBounds(b.x, b.y, b.width, b.height);
         }
         if (root.getGlassPane() != null) {
-            root.getGlassPane().setBounds(i.left, i.top, w, h);
+            root.getGlassPane().setBounds(b.x, b.y, b.width, b.height);
+        }
+
+        DecorationsHandler.getSharedInstance().adjustContentArea(root, b);
+
+        layoutContent(root, b.x, b.y, b.width, b.height);
     }
 
+    public void layoutContent(final JRootPane root, final int x, final int y, final int w, final int h) {
+        int nextY = y;
         JComponent titlePane = getTitlePane(root);
         if (titlePane != null) {
             Dimension tpd = titlePane.getPreferredSize();
             if (tpd != null) {
                 int tpHeight = tpd.height;
-                titlePane.setBounds(0, 0, w, tpHeight);
+                titlePane.setBounds(x, y, w, tpHeight);
                 nextY += tpHeight;
             }
         }
         if (root.getJMenuBar() != null) {
             Dimension mbd = root.getJMenuBar().getPreferredSize();
-            root.getJMenuBar().setBounds(0, nextY, w, mbd.height);
+            root.getJMenuBar().setBounds(x, nextY, w, mbd.height);
             nextY += mbd.height;
         }
         if (root.getContentPane() != null) {
-            root.getContentPane().setBounds(0, nextY, w, h < nextY ? 0 : h - nextY);
+            root.getContentPane().setBounds(x, nextY, w, h < nextY ? 0 : h - nextY);
         }
     }
 

core/src/main/java/com/github/weisj/darklaf/util/DarkUIUtil.java

@@ -61,17 +61,29 @@ public final class DarkUIUtil {
         if (insets != null && rect != null) {
             rect.x += insets.left;
             rect.y += insets.top;
-            rect.width -= (insets.right + rect.x);
+            rect.width -= (insets.right + insets.left);
-            rect.height -= (insets.bottom + rect.y);
+            rect.height -= (insets.bottom + insets.top);
         }
     }
 
+    public static Insets addInsets(final Insets ins1, final Insets ins2) {
+        if (ins2 == null) return ins1;
+        if (ins1 != null) {
+            ins1.left += ins2.left;
+            ins1.right += ins2.right;
+            ins1.top += ins2.top;
+            ins1.bottom += ins2.bottom;
+            return ins1;
+        }
+        return null;
+    }
+
     public static void removeInsets(final Rectangle rectangle, final Insets insets) {
-        if (insets != null) {
+        if (insets != null && rectangle != null) {
-            rectangle.x += insets.left;
+            rectangle.x -= insets.left;
-            rectangle.y += insets.top;
+            rectangle.y -= insets.top;
-            rectangle.width -= insets.left + insets.right;
+            rectangle.width += insets.left + insets.right;
-            rectangle.height -= insets.top + insets.bottom;
+            rectangle.height += insets.top + insets.bottom;
         }
     }
 

core/src/test/java/ui/ComponentDemo.java

@@ -57,6 +57,7 @@ public interface ComponentDemo {
 
     static void showDemo(final ComponentDemo demo, final Dimension dimension) {
         SwingUtilities.invokeLater(() -> {
+            LafManager.setDecorationsEnabled(true);
             LafManager.install(demo.createTheme());
             JFrame frame = new JFrame();
             frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

macos/src/main/java/com/github/weisj/darklaf/platform/macos/ui/MacOSTitlePane.java

@@ -144,11 +144,6 @@ public class MacOSTitlePane extends CustomTitlePane {
         decorationInformation = null;
     }
 
-    @Override
-    public Insets getWindowSizeAdjustment() {
-        return new Insets(0, 0, 0, 0);
-    }
-
     private void installListeners() {
         if (window != null && useCustomTitle()) {
             windowListener = new WindowHandler();

platform-base/src/main/java/com/github/weisj/darklaf/platform/decorations/CustomTitlePane.java

@@ -39,8 +39,6 @@ public abstract class CustomTitlePane extends JComponent {
      */
     protected abstract void install();
 
-    public abstract Insets getWindowSizeAdjustment();
-
     @Override
     public void addNotify() {
         super.addNotify();

platform-base/src/main/java/com/github/weisj/darklaf/platform/decorations/DecorationsProvider.java

@@ -65,10 +65,26 @@ public interface DecorationsProvider {
     /**
      * Initialize the window of a popup menu.
      */
-    default void installPopupMenu(final Window window) {}
+    default void installPopupWindow(final Window window) {}
 
     /**
      * Uninstall the window of a popup menu.
      */
     default void uninstallPopupWindow(final Window window) {}
+
+    /**
+     * Adjusts the content area.
+     *
+     * @param root the corresponding root pane.
+     * @param rect the proposed content area.
+     */
+    default void adjustContentArea(final JRootPane root, final Rectangle rect) {}
+
+    /**
+     * Adjust the window insets.
+     *
+     * @param window the corresponding window.
+     * @param i      the insets to adjust.
+     */
+    default void adjustWindowInsets(final Window window, final Insets i) {}
 }

windows/build.gradle.kts

@@ -32,8 +32,8 @@ library {
     binaries.whenElementFinalized(CppSharedLibrary::class) {
         linkTask.get().linkerArgs.addAll(
             when (toolChain) {
-                is Gcc, is Clang -> listOf("-ldwmapi", "-lGdi32", "-luser32", "-ladvapi32")
+                is Gcc, is Clang -> listOf("-ldwmapi", "-lGdi32", "-luser32", "-ladvapi32", "-Shell32")
-                is VisualCpp -> listOf("dwmapi.lib", "user32.lib", "Gdi32.lib", "Advapi32.lib")
+                is VisualCpp -> listOf("dwmapi.lib", "user32.lib", "Gdi32.lib", "Advapi32.lib", "Shell32.lib")
                 else -> emptyList()
             }
         )

windows/src/main/cpp/Decorations.cpp

@@ -24,47 +24,87 @@
  */
 #include "Decorations.h"
 #include "com_github_weisj_darklaf_platform_windows_JNIDecorationsWindows.h"
-#include <dwmapi.h>
+
-#include <map>
+#ifndef WM_NCUAHDRAWCAPTION
-#include <iostream>
+#define WM_NCUAHDRAWCAPTION (0x00AE)
-#include <winuser.h>
+#endif
+#ifndef WM_NCUAHDRAWFRAME
+#define WM_NCUAHDRAWFRAME (0x00AF)
+#endif
 
 std::map<HWND, WindowWrapper*> wrapper_map = std::map<HWND, WindowWrapper*>();
 
-LRESULT HitTestNCA(HWND hWnd, WPARAM wParam, LPARAM lParam, WindowWrapper *wrapper)
+bool Maximized(HWND hwnd)
+{
+    WINDOWPLACEMENT placement;
+    if (!GetWindowPlacement(hwnd, &placement))
+        return false;
+    return placement.showCmd == SW_MAXIMIZE;
+}
+
+LRESULT HandleHitTest(WindowWrapper *wrapper, int x, int y)
 {
     if (wrapper->popup_menu)
         return HTCLIENT;
-    // Get the point coordinates for the hit test.
+
-    POINT ptMouse = { GET_X_LPARAM(lParam),
+    POINT ptMouse = { x,
-                      GET_Y_LPARAM(lParam) };
+                      y };
 
     // Get the window rectangle.
     RECT rcWindow;
-    GetWindowRect(hWnd, &rcWindow);
+    GetWindowRect(wrapper->window, &rcWindow);
 
     // Determine if the hit test is for resizing. Default middle (1,1).
     USHORT uRow = 1;
     USHORT uCol = 1;
 
-    // Determine if the point is at the top or bottom of the window.
+    if (!Maximized(wrapper->window))
-    if (ptMouse.y >= rcWindow.top && ptMouse.y < rcWindow.top + 5)
     {
+        /* The horizontal frame should be the same size as the vertical frame,
+         since the NONCLIENTMETRICS structure does not distinguish between them */
+        int frame_size = GetSystemMetrics(SM_CXFRAME) + GetSystemMetrics(SM_CXPADDEDBORDER);
+        /* The diagonal size handles are wider than the frame */
+        int diagonal_width = frame_size * 2 + GetSystemMetrics(SM_CXBORDER);
+
+        bool top = ptMouse.y >= rcWindow.top && ptMouse.y < rcWindow.top + frame_size;
+        bool bottom = !top && (ptMouse.y < rcWindow.bottom && ptMouse.y >= rcWindow.bottom - frame_size);
+
+        bool left = ptMouse.x >= rcWindow.left && ptMouse.x < rcWindow.left + frame_size;
+        bool right = !left && (ptMouse.x < rcWindow.right && ptMouse.x >= rcWindow.right - frame_size);
+
+        bool diag_top = ptMouse.y >= rcWindow.top && ptMouse.y < rcWindow.top + diagonal_width;
+        bool diag_bottom = !diag_top && (ptMouse.y < rcWindow.bottom && ptMouse.y >= rcWindow.bottom - diagonal_width);
+
+        bool diag_left = ptMouse.x >= rcWindow.left && ptMouse.x < rcWindow.left + frame_size;
+        bool diag_right = !diag_left && (ptMouse.x < rcWindow.right && ptMouse.x >= rcWindow.right - diagonal_width);
+
+        if (top)
             uRow = 0;
-    }
+        if (bottom)
-    else if (ptMouse.y < rcWindow.bottom && ptMouse.y >= rcWindow.bottom - 5)
-    {
             uRow = 2;
-    }
 
-    // Determine if the point is at the left or right of the window.
+        if (top || bottom)
-    if (ptMouse.x >= rcWindow.left && ptMouse.x < rcWindow.left + 5)
         {
-        uCol = 0; // left side
+            if (diag_left)
+                uCol = 0;
+            else if (diag_right)
+                uCol = 2;
         }
-    else if (ptMouse.x < rcWindow.right && ptMouse.x >= rcWindow.right - 5)
+        else
         {
-        uCol = 2; // right side
+            if (left)
+                uCol = 0;
+            if (right)
+                uCol = 2;
+
+            if (left || right)
+            {
+                if (diag_top)
+                    uRow = 0;
+                else if (diag_bottom)
+                    uRow = 2;
+            }
+        }
     }
 
     // Hit test (HTTOPLEFT, ... HTBOTTOMRIGHT)
@@ -76,12 +116,12 @@ LRESULT HitTestNCA(HWND hWnd, WPARAM wParam, LPARAM lParam, WindowWrapper *wrapp
                                  HTRIGHT },
                                { HTBOTTOMLEFT,
                                  HTBOTTOM,
-                                 HTBOTTOMRIGHT }, };
+                                 HTBOTTOMRIGHT } };
     LRESULT hit = hitTests[uRow][uCol];
     if (hit == HTNOWHERE || !wrapper->resizable)
     {
         //Handle window drag.
-        if (ptMouse.y < rcWindow.top + wrapper->height && ptMouse.x >= rcWindow.left + wrapper->left
+        if (ptMouse.y < rcWindow.top + wrapper->title_height && ptMouse.x >= rcWindow.left + wrapper->left
             && ptMouse.x <= rcWindow.right - wrapper->right)
         {
             return HTCAPTION;
@@ -94,12 +134,54 @@ LRESULT HitTestNCA(HWND hWnd, WPARAM wParam, LPARAM lParam, WindowWrapper *wrapp
     }
 }
 
-bool Maximized(HWND hwnd)
+void UpdateRegion(WindowWrapper *wrapper)
 {
-    WINDOWPLACEMENT placement;
+    if (wrapper->popup_menu)
-    if (!GetWindowPlacement(hwnd, &placement))
+        return;
-        return false;
+    RECT old_rgn = wrapper->rgn;
-    return placement.showCmd == SW_MAXIMIZE;
+
+    if (Maximized(wrapper->window))
+    {
+        WINDOWINFO wi;
+        wi.cbSize = sizeof(WINDOWINFO);
+        GetWindowInfo(wrapper->window, &wi);
+
+        /* For maximized windows, a region is needed to cut off the non-client
+         borders that hang over the edge of the screen */
+        wrapper->rgn.left = wi.rcClient.left - wi.rcWindow.left;
+        wrapper->rgn.top = wi.rcClient.top - wi.rcWindow.top;
+        wrapper->rgn.right = wi.rcClient.right - wi.rcWindow.left;
+        wrapper->rgn.bottom = wi.rcClient.bottom - wi.rcWindow.top;
+
+    }
+    else
+    {
+        /* Don't mess with the region when composition is enabled and the
+         window is not maximized, otherwise it will lose its shadow */
+        wrapper->rgn.left = 0;
+        wrapper->rgn.top = 0;
+        wrapper->rgn.right = 0;
+        wrapper->rgn.bottom = 0;
+    }
+
+    /* Avoid unnecessarily updating the region to avoid unnecessary redraws */
+    if (EqualRect(&wrapper->rgn, &old_rgn))
+        return;
+    /* Treat empty regions as NULL regions */
+    RECT empty = { 0 };
+    if (EqualRect(&wrapper->rgn, &empty))
+        SetWindowRgn(wrapper->window, NULL, TRUE);
+    else
+        SetWindowRgn(wrapper->window, CreateRectRgnIndirect(&wrapper->rgn), TRUE);
+}
+
+bool AutoHideTaskbar(UINT edge, RECT mon)
+{
+    APPBARDATA data;
+    data.cbSize = sizeof(APPBARDATA);
+    data.uEdge = edge;
+    data.rc = mon;
+    return SHAppBarMessage(ABM_GETAUTOHIDEBAREX, &data);
 }
 
 void AdjustMaximizedClientArea(HWND window, RECT &rect)
@@ -107,36 +189,94 @@ void AdjustMaximizedClientArea(HWND window, RECT &rect)
     if (!Maximized(window))
         return;
 
-    auto monitor = MonitorFromWindow(window, MONITOR_DEFAULTTONULL);
+    HMONITOR monitor = MonitorFromWindow(window, MONITOR_DEFAULTTOPRIMARY);
     if (!monitor)
         return;
 
     MONITORINFO monitor_info {};
-    monitor_info.cbSize = sizeof(monitor_info);
+    monitor_info.cbSize = sizeof(MONITORINFO);
-    if (!GetMonitorInfoW(monitor, &monitor_info))
+    if (!GetMonitorInfo(monitor, &monitor_info))
         return;
 
     rect = monitor_info.rcWork;
 }
 
-void AdjustMinMaxInfo(HWND hwnd, LPARAM lParam)
+void HandleNCCalcSize(WindowWrapper *wrapper, WPARAM wparam, LPARAM lparam)
 {
-    HMONITOR hPrimaryMonitor = MonitorFromWindow(nullptr, MONITOR_DEFAULTTOPRIMARY);
+    union
-    HMONITOR hTargetMonitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
+    {
-
+            LPARAM lparam;
-    MONITORINFO primaryMonitorInfo { sizeof(MONITORINFO) };
+            RECT *rect;
-    MONITORINFO targetMonitorInfo { sizeof(MONITORINFO) };
+    } params;
-
+    params.lparam = lparam;
-    GetMonitorInfo(hPrimaryMonitor, &primaryMonitorInfo);
+
-    GetMonitorInfo(hTargetMonitor, &targetMonitorInfo);
+    /* DefWindowProc must be called in both the maximized and non-maximized
-
+     cases, otherwise tile/cascade windows won't work */
-    MINMAXINFO *min_max_info = reinterpret_cast<MINMAXINFO*>(lParam);
+    RECT nonclient = *params.rect;
-    RECT max_rect = primaryMonitorInfo.rcWork;
+    DefWindowProc(wrapper->window, WM_NCCALCSIZE, wparam, lparam);
-    RECT target_rect = targetMonitorInfo.rcWork;
+    RECT client = *params.rect;
-    min_max_info->ptMaxSize.x = target_rect.right - target_rect.left;
+
-    min_max_info->ptMaxSize.y = target_rect.bottom - target_rect.top;
+    if (Maximized(wrapper->window))
-    min_max_info->ptMaxPosition.x = max_rect.left;
+    {
-    min_max_info->ptMaxPosition.y = max_rect.top;
+        WINDOWINFO wi;
+        wi.cbSize = sizeof(wi);
+        GetWindowInfo(wrapper->window, &wi);
+
+        /* Maximized windows always have a non-client border that hangs over
+         the edge of the screen, so the size proposed by WM_NCCALCSIZE is
+         fine. Just adjust the top border to remove the window title. */
+        (*params.rect).left = client.left;
+        (*params.rect).top = nonclient.top + wi.cyWindowBorders;
+        (*params.rect).right = client.right;
+        (*params.rect).bottom = client.bottom;
+
+        HMONITOR mon = MonitorFromWindow(wrapper->window, MONITOR_DEFAULTTOPRIMARY);
+        MONITORINFO mi;
+        mi.cbSize = sizeof(mi);
+        GetMonitorInfoW(mon, &mi);
+
+        /*
+         * If the client rectangle is the same as the monitor's rectangle,
+         * the shell assumes that the window has gone fullscreen, so it removes
+         * the topmost attribute from any auto-hide appbars, making them
+         * inaccessible. To avoid this, reduce the size of the client area by
+         * one pixel on a certain edge. The edge is chosen based on which side
+         * of the monitor is likely to contain an auto-hide appbar, so the
+         * missing client area is covered by it.
+         */
+        if (EqualRect(params.rect, &mi.rcMonitor))
+        {
+            if (AutoHideTaskbar(ABE_BOTTOM, mi.rcMonitor))
+                params.rect->bottom--;
+            else if (AutoHideTaskbar(ABE_LEFT, mi.rcMonitor))
+                params.rect->left++;
+            else if (AutoHideTaskbar(ABE_TOP, mi.rcMonitor))
+                params.rect->top++;
+            else if (AutoHideTaskbar(ABE_RIGHT, mi.rcMonitor))
+                params.rect->right--;
+        }
+    }
+    else
+    {
+        /* For the non-maximized case, set the output RECT to what it was
+         before WM_NCCALCSIZE modified it. This will make the client size the
+         same as the non-client size. */
+        *params.rect = nonclient;
+    }
+}
+
+void HandleWindowPosChanged(WindowWrapper *wrapper, const WINDOWPOS *pos)
+{
+    RECT client;
+    GetClientRect(wrapper->window, &client);
+    LONG old_width = wrapper->width;
+    LONG old_height = wrapper->height;
+    wrapper->width = client.right;
+    wrapper->height = client.bottom;
+    bool client_changed = wrapper->width != old_width || wrapper->height != old_height;
+
+    if (client_changed || (pos->flags & SWP_FRAMECHANGED))
+        UpdateRegion(wrapper);
 }
 
 void PaintBackground(HWND hwnd, WPARAM wParam, WindowWrapper *wrapper)
@@ -152,45 +292,49 @@ LRESULT CALLBACK WindowWrapper::WindowProc(_In_ HWND hwnd, _In_ UINT uMsg, _In_
     HWND handle = reinterpret_cast<HWND>(hwnd);
     auto wrapper = wrapper_map[handle];
 
-    if (uMsg == WM_NCACTIVATE)
+    switch(uMsg)
     {
+        case WM_NCACTIVATE:
         return TRUE;
-    }
+        case WM_NCCALCSIZE:
-    else if (uMsg == WM_NCCALCSIZE)
-    {
         if (wParam == TRUE)
         {
-            NCCALCSIZE_PARAMS& params = *reinterpret_cast<NCCALCSIZE_PARAMS*>(lParam);
+            HandleNCCalcSize(wrapper, wParam, lParam);
-            AdjustMaximizedClientArea(handle, params.rgrc[0]);
+            UpdateRegion(wrapper);
-            return TRUE;
+            return 0;
-        }
-    }
-    else if (uMsg == WM_GETMINMAXINFO)
-    {
-        AdjustMinMaxInfo(hwnd, lParam);
-        return FALSE;
-    }
-    else if (uMsg == WM_NCHITTEST)
-    {
-        return HitTestNCA(hwnd, wParam, lParam, wrapper);
         }
-    else if (uMsg == WM_MOVE)
+        break;
-    {
+        case WM_NCHITTEST:
+        return HandleHitTest(wrapper, GET_X_LPARAM(lParam),GET_Y_LPARAM(lParam));
+        case WM_MOVE:
         wrapper->moving = wrapper->move_mode;
-    }
+        break;
-    else if (uMsg == WM_ENTERSIZEMOVE)
+        case WM_ENTERSIZEMOVE:
-    {
         wrapper->move_mode = TRUE;
-    }
+        break;
-    else if (uMsg == WM_EXITSIZEMOVE)
+        case WM_EXITSIZEMOVE:
-    {
         wrapper->moving = FALSE;
         wrapper->move_mode = FALSE;
-    }
+        break;
-    else if ((uMsg == WM_PAINT || uMsg == WM_ERASEBKGND) && wrapper->bgBrush)
+        case WM_ERASEBKGND:
-    {
+        case WM_PAINT:
-        if (!wrapper->moving) PaintBackground(hwnd, wParam, wrapper);
+        if (!wrapper->bgBrush)
-        if (uMsg == WM_ERASEBKGND) return TRUE;
+        break;
+        if (!wrapper->moving)
+        PaintBackground(hwnd, wParam, wrapper);
+        if (uMsg == WM_ERASEBKGND)
+        return TRUE;
+        break;
+        case WM_NCUAHDRAWCAPTION:
+        case WM_NCUAHDRAWFRAME:
+        /* These undocumented messages are sent to draw themed window borders.
+         Block them to prevent drawing borders over the client area. */
+        return 0;
+        case WM_WINDOWPOSCHANGED:
+        HandleWindowPosChanged(wrapper, (WINDOWPOS*)lParam);
+        break;
+        default:
+        break;
     }
 
     return CallWindowProc(wrapper->prev_proc, hwnd, uMsg, wParam, lParam);
@@ -217,7 +361,7 @@ Java_com_github_weisj_darklaf_platform_windows_JNIDecorationsWindows_updateValue
     {
         wrap->left = l;
         wrap->right = r;
-        wrap->height = h;
+        wrap->title_height = h;
     }
 }
 
@@ -236,15 +380,16 @@ void ExtendClientFrame(HWND handle)
 {
     MARGINS margins = { 0,
                         0,
-                        0,
+                        1,
-                        1 };
+                        0 };
     DwmExtendFrameIntoClientArea(handle, &margins);
 }
 
-void SetupWindowStyle(HWND handle)
+void SetupWindowStyle(HWND handle, bool is_popup)
 {
     auto style = GetWindowLongPtr(handle, GWL_STYLE);
-    SetWindowLongPtr(handle, GWL_STYLE, (style | WS_THICKFRAME));
+    style |= WS_THICKFRAME;
+    SetWindowLongPtr(handle, GWL_STYLE, style);
 }
 
 bool InstallDecorations(HWND handle, bool is_popup)
@@ -254,12 +399,13 @@ bool InstallDecorations(HWND handle, bool is_popup)
     if (it != wrapper_map.end())
         return false;
 
-    SetupWindowStyle(handle);
+    SetupWindowStyle(handle, is_popup);
     ExtendClientFrame(handle);
 
     WNDPROC proc = reinterpret_cast<WNDPROC>(GetWindowLongPtr(handle, GWLP_WNDPROC));
 
     WindowWrapper *wrapper = new WindowWrapper();
+    wrapper->window = handle;
     wrapper->prev_proc = proc;
     wrapper->popup_menu = is_popup;
     wrapper_map[handle] = wrapper;

windows/src/main/cpp/Decorations.h

@@ -25,6 +25,11 @@
 #include <stdio.h>
 #include <windows.h>
 #include <windowsx.h>
+#include <dwmapi.h>
+#include <map>
+#include <iostream>
+#include <shellapi.h>
+#include <winuser.h>
 
 class WindowWrapper
 {
@@ -33,12 +38,19 @@ class WindowWrapper
         bool popup_menu = false;
         bool moving = false;
         bool move_mode = false;
+        bool maximized = false;
         WNDPROC prev_proc;
         HBRUSH bgBrush;
 
+        HWND window;
+        int width;
+        int height;
+
+        RECT rgn;
+
         int left = 0;
         int right = 0;
-        int height = 0;
+        int title_height = 0;
 
         static LRESULT CALLBACK WindowProc(_In_ HWND hwnd, _In_ UINT uMsg, _In_ WPARAM wParam, _In_ LPARAM lParam);
 };

windows/src/main/java/com/github/weisj/darklaf/platform/windows/WindowsDecorationsProvider.java

@@ -28,6 +28,7 @@ import java.awt.*;
 import java.util.Properties;
 
 import javax.swing.*;
+import javax.swing.border.Border;
 
 import com.github.weisj.darklaf.PropertyLoader;
 import com.github.weisj.darklaf.icons.IconLoader;
@@ -53,18 +54,21 @@ public class WindowsDecorationsProvider implements DecorationsProvider {
     }
 
     @Override
-    public void installPopupMenu(final Window window) {
+    public void installPopupWindow(final Window window) {
         if (!window.isDisplayable()) {
             window.addNotify();
         }
         long hwnd = PointerUtil.getHWND(window);
         if (hwnd != 0) {
-            if (JNIDecorationsWindows.installPopupMenuDecorations(hwnd)) {
+            if (JNIDecorationsWindows.installPopupMenuDecorations(hwnd) && window instanceof RootPaneContainer) {
-                Color bg = window.getBackground();
+                JRootPane rootPane = ((RootPaneContainer) window).getRootPane();
+                Color bg = rootPane != null ? rootPane.getBackground() : null;
+                if (bg != null) {
                     JNIDecorationsWindows.setBackground(hwnd, bg.getRed(), bg.getGreen(), bg.getBlue());
                 }
             }
         }
+    }
 
     @Override
     public void uninstallPopupWindow(final Window window) {
@@ -77,6 +81,28 @@ public class WindowsDecorationsProvider implements DecorationsProvider {
         }
     }
 
+    @Override
+    public void adjustContentArea(final JRootPane root, final Rectangle rect) {
+        Border border = root.getBorder();
+        if (border != null) {
+            Insets ins = border.getBorderInsets(root);
+            rect.x -= ins.left;
+            rect.y -= ins.top;
+        }
+    }
+
+    @Override
+    public void adjustWindowInsets(final Window window, final Insets i) {
+        // Compensate for the insets of the native window peer that include the decorations.
+        if (window != null) {
+            Insets insets = window.getInsets();
+            i.left -= insets.left;
+            i.right -= insets.right;
+            i.top -= insets.top;
+            i.bottom -= insets.bottom;
+        }
+    }
+
     @Override
     public void loadDecorationProperties(final Properties properties, final UIDefaults currentDefaults) {
         IconLoader iconLoader = IconLoader.get(WindowsDecorationsProvider.class);

windows/src/main/java/com/github/weisj/darklaf/platform/windows/ui/WindowsTitlePane.java

@@ -32,6 +32,7 @@ import java.util.List;
 
 import javax.accessibility.AccessibleContext;
 import javax.swing.*;
+import javax.swing.border.Border;
 import javax.swing.plaf.UIResource;
 
 import sun.awt.SunToolkit;
@@ -115,6 +116,7 @@ public class WindowsTitlePane extends CustomTitlePane {
     private Color activeBackground;
     private Color activeForeground;
     private Color border;
+    private Border oldBorder;
 
     public WindowsTitlePane(final JRootPane root, final int decorationStyle, final Window window) {
         this.rootPane = root;
@@ -169,16 +171,6 @@ public class WindowsTitlePane extends CustomTitlePane {
         }
     }
 
-    @Override
-    public Insets getWindowSizeAdjustment() {
-        // Compensate for the insets of the native window peer that include the decorations.
-        Insets insets = window != null && windowHandle != 0
-                ? window.getInsets()
-                : new Insets(0, 0, 0, 0);
-        insets.set(-insets.top, -insets.left, -insets.bottom, -insets.right);
-        return insets;
-    }
-
     private void uninstallListeners() {
         if (window != null) {
             window.removeWindowListener(windowListener);
@@ -507,11 +499,14 @@ public class WindowsTitlePane extends CustomTitlePane {
             if (frame != null) {
                 JRootPane rootPane = getRootPane();
 
-                if (((state & Frame.MAXIMIZED_BOTH) != 0)
+                if (((state & Frame.MAXIMIZED_BOTH) != 0)) {
-                    && (rootPane.getBorder() == null
+                    oldBorder = rootPane.getBorder();
-                        || (rootPane.getBorder() instanceof UIResource))
+                    LookAndFeel.uninstallBorder(rootPane);
-                    && frame.isShowing()) {
+                } else {
-                    rootPane.setBorder(null);
+                    Border border = rootPane.getBorder();
+                    if (oldBorder != null && border == null || border instanceof UIResource) {
+                        rootPane.setBorder(oldBorder);
+                    }
                 }
 
                 if (frame.isResizable()) {