private void repaintRolloverLaterOnce( int oldIndex ) {
		if( repaintRolloverPending )
			return;
		repaintRolloverPending = true;

		EventQueue.invokeLater( () -> {
			repaintRolloverPending = false;
			if( tabPane == null )
				return;

			int index = getRolloverTab();
			if( index != oldIndex ) {
				// repaint old and new hover tabs
				repaintTab( oldIndex );
				repaintTab( index );
			}
		} );
	}
Repaint rollover tab, but deferred and only once.
This is to avoid unnecessary repaints in case of temporary changes to rollover tab.

E.g. when moving mouse over a single tab, a re-layout may occur and
set rollover tab to -1, in BasicTabbedPaneUI.TabbedPaneLayout.layoutContainer() and
BasicTabbedPaneUI.TabbedPaneScrollLayout.layoutContainer(), and subsequently
change rollover tab back to previous value.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTabbedPaneUI.java