No Input accepted after suspend-resume on android

After a Qt application was suspended by the android system for a long time then after resuming it doesn't accept any input from mouse or keyboard.
The only exception is the main menu if there is one. The usual File->Quit will work in this situation if and only if it doesn't try to open a dialogue.
This behaviour can easily be reproduced:
1. Start Qt app on android
2. force android into standby mode or wait until the screenblanker switches the screen off
3. wait for more then 10 minutes
4. wake up your device and the Qt app with it
5. try to perform any input on buttons, input fields or whatever