Delay scroll popup menu container initialisation.

core/src/main/java/com/github/weisj/darklaf/ui/popupmenu/DarkPopupMenuUI.java

@@ -80,13 +80,17 @@ public class DarkPopupMenuUI extends BasicPopupMenuUI {
 
     @Override
     public void installDefaults() {
-        if (!(popupMenu instanceof ScrollPopupMenu)) {
-            popupMenuContainer = new PopupMenuContainer();
-        }
         super.installDefaults();
         popupMenu.putClientProperty(DarkPopupFactory.KEY_START_HIDDEN, true);
     }
 
+    private PopupMenuContainer getPopupMenuContainer() {
+        if (popupMenuContainer == null && !(popupMenu instanceof ScrollPopupMenu)) {
+            popupMenuContainer = new PopupMenuContainer();
+        }
+        return popupMenuContainer;
+    }
+
     @Override
     protected void installListeners() {
         super.installListeners();
@@ -95,8 +99,9 @@ public class DarkPopupMenuUI extends BasicPopupMenuUI {
 
     @Override
     public Popup getPopup(final JPopupMenu popup, final int x, final int y) {
-        if (popupMenuContainer == null) return super.getPopup(popup, x, y);
+        PopupMenuContainer container = getPopupMenuContainer();
+        if (container == null) return super.getPopup(popup, x, y);
         int maxHeight = DarkUIUtil.getScreenBounds(popup, x, y, false).height;
-        return popupMenuContainer.createPopup(popup, x, y, maxHeight);
+        return container.createPopup(popup, x, y, maxHeight);
     }
 }

core/src/main/java/com/github/weisj/darklaf/ui/popupmenu/PopupMenuContainer.java

@@ -39,18 +39,28 @@ import com.github.weisj.darklaf.util.DarkUIUtil;
 
 public class PopupMenuContainer extends JPanel {
 
-    private final JScrollPane scrollPane;
-    private final MenuKeyListener menuKeyListener;
-    private final PopupMenuListener menuListener;
-    private final JPanel view;
+    private JScrollPane scrollPane;
+    private JPanel view;
+
+    private MenuKeyListener menuKeyListener;
+    private PopupMenuListener menuListener;
     private JPopupMenu popupMenu;
 
     public PopupMenuContainer() {
         super(new BorderLayout());
+    }
+
+    private void initComponents() {
+        if (view == null) {
             view = new JPanel(new BorderLayout());
             OverlayScrollPane overlayScrollPane = createScrollPane(view);
             scrollPane = overlayScrollPane.getScrollPane();
             add(overlayScrollPane, BorderLayout.CENTER);
+        }
+    }
+
+    protected MenuKeyListener getMenuKeyListener() {
+        if (menuKeyListener == null) {
             menuKeyListener = new MenuKeyListener() {
                 @Override
                 public void menuKeyTyped(final MenuKeyEvent e) {}
@@ -72,6 +82,12 @@ public class PopupMenuContainer extends JPanel {
                 @Override
                 public void menuKeyReleased(final MenuKeyEvent e) {}
             };
+        }
+        return menuKeyListener;
+    }
+
+    protected PopupMenuListener getMenuListener() {
+        if (menuListener == null) {
             menuListener = new PopupMenuAdapter() {
                 @Override
                 public void popupMenuWillBecomeInvisible(final PopupMenuEvent e) {
@@ -90,18 +106,22 @@ public class PopupMenuContainer extends JPanel {
                 }
             };
         }
+        return menuListener;
+    }
 
     public void setPopupMenu(final JPopupMenu popupMenu) {
+        MenuKeyListener keyListener = getMenuKeyListener();
+        PopupMenuListener popupMenuListener = getMenuListener();
         if (this.popupMenu != null) {
-            this.popupMenu.removeMenuKeyListener(menuKeyListener);
-            this.popupMenu.removePopupMenuListener(menuListener);
+            this.popupMenu.removeMenuKeyListener(keyListener);
+            this.popupMenu.removePopupMenuListener(popupMenuListener);
         }
         this.popupMenu = popupMenu;
         if (popupMenu != null) {
-            popupMenu.removeMenuKeyListener(menuKeyListener);
-            popupMenu.removePopupMenuListener(menuListener);
-            popupMenu.addMenuKeyListener(menuKeyListener);
-            popupMenu.addPopupMenuListener(menuListener);
+            popupMenu.removeMenuKeyListener(keyListener);
+            popupMenu.removePopupMenuListener(popupMenuListener);
+            popupMenu.addMenuKeyListener(keyListener);
+            popupMenu.addPopupMenuListener(popupMenuListener);
         }
     }
 
@@ -113,6 +133,7 @@ public class PopupMenuContainer extends JPanel {
             popupMenu.setBorderPainted(true);
             return PopupFactory.getSharedInstance().getPopup(popupMenu.getInvoker(), popupMenu, posX, posY);
         } else {
+            initComponents();
             int increment = 1;
             if (popupMenu.getComponentCount() > 0) {
                 increment = Math.max(1, popupMenu.getComponent(0).getPreferredSize().height / 2);