private Component findActiveRendererComponent() {
			int count = rendererPane.getComponentCount();
			for( int i = 0; i < count; i++ ) {
				Component c = rendererPane.getComponent( i );
				if( c.getWidth() > 0 && c.getHeight() > 0 )
					return c;
			}
			return null;
		}
A CellRendererPane may contain multiple components, if multiple renderers
are used. Inactive renderer components have size {@code 0x0}.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTableUI.java