KWinInternal::DetectWidgetBase Form3 0 0 523 325 Form3 unnamed 0 spacer1 Vertical Expanding 20 40 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: line1 HLine Sunken Horizontal textLabel9 Information About Selected Window buttonGroup1 unnamed use_class Use window &class (whole application) Alt+C 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 do not 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.