Comment 44 for bug 923410

Case of Ubuntu inside a VM is not something we can easily fix, as we need to globally listen for any Alt key presses. There's no easy way around this.

The tap detection code does indeed take into account all other keypresses. The HUD should only show if you press & release the Alt key quickly, and having pressed no other key in the mean time. Perhaps some keys are not reported correctly. xev output would help us.

Any steps to reproduce and information about your system would be useful. External/internal keyboard, computer model, etc.
-G