Add shortcuts in main buttons of MUI prefs

[Samir Hawamdeh]

Problem

The main buttons in MUI prefs lacks a proper shortcuts in order to select them via keyboard

I mean that one:

Save
Use
Test
Cancel

In english they might become:

_Save
_Use
_Test
_Cancel

Of course If this combination does not interferise with other shortcuts present

[Thore Böckelmann]

Although this sounds like a sensible request it might turn out to be not possible as easy as it seems. The point is that certain shortcut characters are already used otherwise. For english this work, but for example for german the translation for "Cancel" is "Abbrechen" and "A" is used for the "Save as" menu item already. I could use the "c" like in english, but I think you see the global problem to accomplish this task in all languages. For the italian translation we have the same problem with "Annulla". "n" and "l" are currently unused.

What makes the problem even worse are 3rd party .mcp modules. Usually such modules should not use any shortcuts for any of their labels/objects. MUI will try to distribute as many available shortcuts as possible automatically. But if a module does this itself already and uses "U" as shortcut for one of its own objects then MUI's own "Use" button will have a duplicate shortcut.