Comment 0 for bug 1264821

TJ (tj) wrote :

When using multiple X screens (3 in this case), kscreenlocker-greet behaves very badly and insecurely.

It appears to be drawing the desktop background image/screensaver images for all three X screens to the primary screen (0) and doesn't blank/screensave the monitors belonging to screens 1 and 2 (which leaves their contents in view), and it displays 2, maybe 3 greeter dialogs (1 may be hidden) on the primary X screen, but only accepts typed password input in 1 of them (the primary X screen's dialog).

Reading the source-code at ksmserver/screenlocker/greeter/ UnlockApp::desktopResized() it appears to iterate the screens via desktop()->screenCount() but assumes there is only one X display when showing the ScreenSaverWindow.

There may be an underlying dependencies on the QT libraries that cause/affect this but someone familiar with the code would need to investigate it.