private static String toString( Color c ) {
		if( c == null )
			return "null";

		StringBuilder buf = new StringBuilder( 150 );

		buf.append( "<tt>" ); // <tt> is similar to <code>, but uses same font size as body
		buf.append( (c.getAlpha() != 255)
			? String.format( "#%06x%02x", c.getRGB() & 0xffffff, (c.getRGB() >> 24) & 0xff )
			: String.format( "#%06x", c.getRGB() & 0xffffff ) );
		buf.append( "</tt>" );

		if( c instanceof UIResource )
			buf.append( " UI" );

		// color preview
		buf.append( "&nbsp; &nbsp;" )
			.append( "<span style=\"background: " )
			.append( String.format( "#%06x", c.getRGB() & 0xffffff ) ) // Java CSS does not support alpha; see CSS.hexToColor()
			.append( ";\">" )
			.append( "&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;" )
			.append( "</span>" );

		if( c.getAlpha() != 255 )
			buf.append( " " ).append( Math.round( c.getAlpha() / 2.55f ) ).append( '%' );

		return buf.toString();
	}
Installs a key listener into the application that allows enabling and disabling
the UI inspector with the given keystroke (e.g. "ctrl shift alt X").

@param activationKeys a keystroke (e.g. "ctrl shift alt X"), or {@code null} to use "ctrl shift alt X"
flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/FlatInspector.java