I used texmacs long time ago (no qt version). Now I have to do some math stuff with texmacs again. I have installed texmacs on windows 8.1 and Ubuntu 14.04 (virtualbox). On both the alt-modifier (alt-key) won't work. Any idea what could going wrong? I also find no alt-modifier configuration options any more.

On a Ubuntu laptop some key strokes with alt work and some are not.

In math mode alt-shift-v for vectors work but alt-s or alt-shift-s for square roots do not.