@Override
		void hideImpl() {
			if( popupWindow != null )
				removeAllPopupWindowComponentListeners();

			if( dropShadowDelegate != null ) {
				dropShadowDelegate.hide();
				dropShadowDelegate = null;
				dropShadowPanel2 = null;
			}

			if( mediumWeightPanel != null ) {
				hideMediumWeightDropShadow();
				dropShadowPanel = null;
				mediumWeightPanel = null;
			}

			super.hideImpl();

			if( dropShadowWindow != null ) {
				dropShadowWindow.setBackground( oldDropShadowWindowBackground );
				dropShadowWindow = null;
			}

			if( lightComp != null ) {
				lightComp.setBorder( oldBorder );
				lightComp.setOpaque( oldOpaque );
				lightComp = null;
			}
		}
Fixes popup background flashing effect when using dark theme on light platform theme,
where the light popup background is shown for a fraction of a second before
the dark popup content is shown.
This is fixed by setting popup background to content background.
<p>
Defers hiding of heavy weight popup window for an event cycle,
which allows reusing popup window to avoid flicker when "moving" popup.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatPopupFactory.java