Hi,
The Playground and Inspector are using Rubric. And, I am moving all keymappings to use the default Ctrl modifier. It works on Windows (I only still have a problem with Ctrl+m which does not seem to work).
On Linux, it should work, too. Could you please test again and let me know if you can use Ctrl as a modifier?
I know that in the PluggableTextMorph (the default widget used within the default Pharo environment) some commands use Alt and others use Ctrl, but I think the only meaningful way is to support Ctrl because this is what a user of that operating system supposes.
I will still try to get support for Alt as well, but it needs some iterations.
Cheers,
Doru