Я так понял зависит от менеджера окон , можно установить опцию Qt::X11BypassWindowManagerHintя только начинаю в QT работать , подскажите как её применить
QWidget * mainWidget = new QWidget( NULL, Qt::X11BypassWindowManagerHint );
QWidget * window = new QWidget (NULL, Qt::X11BypassWindowMangerHint | Qt::FramelessWindowHint);window->showFullScreen();
Qt::X11BypassWindowManagerHintBypass the window manager completely. This results in a borderless window that is not managed at all (i.e., no keyboard input unless you call QWidget::activateWindow() manually).Qt::FramelessWindowHintProduces a borderless window. The user cannot move or resize a borderless window via the window system. On X11, the result of the flag is dependent on the window manager and its ability to understand Motif and/or NETWM hints. Most existing modern window managers can handle this.
window->show();
window->showFullScreen();