Avoid popup installation if decorations are disabled.

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

@@ -86,11 +86,13 @@ public class DarkPopupFactory extends PopupFactory {
                 window.setFocusableWindowState(true);
             }
 
+            if (DecorationsHandler.getSharedInstance().isCustomDecorationSupported()) {
                 if (install) {
                     DecorationsHandler.getSharedInstance().installPopupWindow(window);
                 } else {
                     DecorationsHandler.getSharedInstance().uninstallPopupWindow(window);
                 }
+            }
             if (startHidden) {
                 ((JComponent) contents).putClientProperty(DarkPopupMenuUI.KEY_MAKE_VISIBLE, true);
                 window.setOpacity(0.0f);