@Override
				public void fillRect( int x, int y, int width, int height ) {
					if( !inPaintSelection &&
						x == 0 && y == 0 && width == rowBounds.width && height == rowBounds.height &&
						this.getColor() == rendererComponent.getBackground() )
					{
						inPaintSelection = true;
						paintCellSelection( this, row, x, y, width, height );
						inPaintSelection = false;
					} else
						super.fillRect( x, y, width, height );
				}
Toggle selection colors from focused to inactive and vice versa.

This is not an optimal solution but much easier than rewriting the whole paint methods.

Using a LaF specific renderer was avoided because often a custom renderer is
already used in applications. Then either the inactive colors are not used,
or the application has to be changed to extend a FlatLaf renderer.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatListUI.java