I've been trying to learn Blender intermittently for about half a year in between other projects. It's now a very important priority for a school course, but throughout my learning I've been stymied because Blender's "CTRL + <letter>" functions don't seem to work on Ubuntu.

With both my current computer - and my previous computer - hitting 'CTRL-Z', for example, does not undo anything - and none of the other CTRL functions seem to be working either. This has remained the case across multiple keyboards, machines, Ubuntu distros, and Blender installations.

I've googled this - thinking this must be a bug - but I can't find anyone else with this problem. Does anyone know any common workarounds, or should I submit a bug report?