@Override
		synchronized public Insets getBorderInsets( Component c, Insets insets ) {
			Insets padding = scale( this.padding );
			if( rendererBorder != null && !(rendererBorder instanceof CellPaddingBorder) ) {
				Insets insideInsets = rendererBorder.getBorderInsets( c );
				insets.top = Math.max( padding.top, insideInsets.top );
				insets.left = Math.max( padding.left, insideInsets.left );
				insets.bottom = Math.max( padding.bottom, insideInsets.bottom );
				insets.right = Math.max( padding.right, insideInsets.right );
			} else {
				insets.top = padding.top;
				insets.left = padding.left;
				insets.bottom = padding.bottom;
				insets.right = padding.right;
			}

			// if used in popup list, add focus width for exact vertical alignment
			// of text in popup list with text in combobox
			insets.left += focusWidth;
			insets.right += focusWidth;

			// style "mac"
			if( c instanceof JComponent ) {
				Boolean macStyleHint = clientPropertyBooleanStrict( (JComponent) c, KEY_MAC_STYLE_HINT, null );
				if( macStyleHint != null ) {
					int indent = MacCheckedItemIcon.INSTANCE.getIconWidth() + scale( MAC_STYLE_GAP );
					if( c.getComponentOrientation().isLeftToRight() )
						insets.left += indent;
					else
						insets.right += indent;
				}
			}

			return insets;
		}
Uninstall border from previously installed component.
Because this border is installed in PopupListCellRenderer.getListCellRendererComponent(),
there is no single place to uninstall it.
This is the reason why this method is called from various places.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java