private static String toString( Class<?> cls, boolean classHierarchy ) {
		StringBuilder buf = new StringBuilder( 100 );
		int level = 0;

		while( cls != null ) {
			if( level > 0 ) {
				if( cls == Object.class )
					break;
				buf.append( "<br>&nbsp;" );
				for( int i = 1; i < level; i++ )
					buf.append( "&nbsp;&nbsp;&nbsp;&nbsp;" );
				buf.append( "\u2570 " );
			}
			level++;

			String name = cls.getName();
			int dot = name.lastIndexOf( '.' );
			String pkg = (dot >= 0) ? name.substring( 0, dot ) : "-";
			String simpleName = (dot >= 0) ? name.substring( dot + 1 ) : name;
			buf.append( simpleName ).append( ' ' ).append( toDimmedText( "(" + pkg + ")" ) );

			if( UIResource.class.isAssignableFrom( cls ) )
				buf.append( " UI" );

			if( !classHierarchy )
				break;

			cls = cls.getSuperclass();
		}

		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