KWinInternal::DetectWidgetBase Form3 0 0 557 335 unnamed textLabel9 Information about the selected window: line1 HLine Sunken Horizontal layout2 unnamed textLabel11 Extra role: textLabel1 Class: textLabel3 Role: type_label textLabel8 Title: class_label role_label title_label machine_label textLabel4 Type: extrarole_label textLabel13 Machine: buttonGroup1 unnamed use_class Use window &class (whole application) true For selecting all windows belonging to a specific application, selecting only window class should usually work. use_role Use window class and window &role (specific window) For selecting a specific window in an application, both window class and window role should be selected. Window class will determine the application and window role the specific window in the application. Many applications don't provide useful window roles though. use_whole_class Use &whole window class (specific window) With some (non-KDE) applications whole window class can be sufficient for selecting a specific window in an application, as they set whole window class to contain both application and window role. spacer1 Vertical Expanding 20 40