Fixed window too large when maximized.

Signed-off-by: weisj <weisj@arcor.de>

src/jniplatform/cpp/JNIDecorations.cpp

@@ -106,13 +106,23 @@ LRESULT CALLBACK WindowWrapper::WindowProc(_In_ HWND hwnd, _In_ UINT uMsg, _In_
     }
     else if (uMsg == WM_GETMINMAXINFO)
     {
+        HMONITOR hPrimaryMonitor = MonitorFromWindow(nullptr, MONITOR_DEFAULTTOPRIMARY);
+        HMONITOR hTargetMonitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
+
+        MONITORINFO primaryMonitorInfo{sizeof(MONITORINFO)};
+        MONITORINFO targetMonitorInfo{sizeof(MONITORINFO)};
+
+        GetMonitorInfo(hPrimaryMonitor, &primaryMonitorInfo);
+        GetMonitorInfo(hTargetMonitor, &targetMonitorInfo);
+
         MINMAXINFO *min_max_info = reinterpret_cast<MINMAXINFO *>(lParam);
-        RECT max_rect;
-        SystemParametersInfo(SPI_GETWORKAREA, 0, &max_rect, 0);
-        min_max_info->ptMaxSize.x = max_rect.right - max_rect.left;
-        min_max_info->ptMaxSize.y = max_rect.bottom - max_rect.top;
-        min_max_info->ptMaxPosition.x = max_rect.left;
-        min_max_info->ptMaxPosition.y = max_rect.top;
+        RECT max_rect = primaryMonitorInfo.rcWork;
+        RECT target_rect = targetMonitorInfo.rcWork;
+        int indent = 2;
+        min_max_info->ptMaxSize.x = target_rect.right - target_rect.left - 2 * indent;
+        min_max_info->ptMaxSize.y = target_rect.bottom - target_rect.top - 2 + indent;
+        min_max_info->ptMaxPosition.x = max_rect.left + indent;
+        min_max_info->ptMaxPosition.y = max_rect.top + indent;
         return 0;
     }