Fullscreen QtQuick Windows ("visibility: Window.Fullscreen") there are several buggy behaviours when interracting with other apps on Windows 7.

1. If you take a screenshot either using the print screen button, or the Snipping Tool (from a 2nd monitor), the fullscreen window is not shown (it is effectively transparent).

2. If you alt-tab away from the fullscreen window, and then select it again in the taskbar it is not shown, but it is actually there - as soon as you click somewhere where a control should be (or maybe the window background?) it appears again!

3. If you alt-tab from the fullscreen window to another window in your Qt app that isn't fullscreen, everything is shown correctly, but as before the fullscreen window is actually still on top and steals all the clicks.

Updating my drivers (Intel HD 4000) didn't help, but I have narrowed the problem down. I have a laptop connected to an external monitor in "extend desktop" mode. The external monitor is set to be the primary display (contains the task bar). The screen-shot problem only occurs if the window is maximised on the external monitor. If it is on the laptop, or on the laptop with the externam monitor disconnected (single display), the screenshot works fine.