KWin::DetectWidgetBase 0 0 523 325 0 20 40 Expanding Qt::Vertical Extra role: false Class: false Role: false false Title: false false false false false Type: false false Machine: false QFrame::HLine QFrame::Sunken Information About Selected Window false 0 Use window &class (whole application) true For selecting all windows belonging to a specific application, selecting only window class should usually work. 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 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. Match also window &title qPixmapFromMimeSource