Bug 458187

SUMMARY
while using the colorize mask tool, any keybind that uses ctrl+shift triggers a temporary toggle of the key stroke editing, very badly conflicting with the very idiomatic ctrl+shift+z redo keybind.
i tried finding any sort of setting to unbind ctrl+shift from this functionality but i failed to do so.

STEPS TO REPRODUCE
1. start editing a colorize mask with the colorize mask tool
2. make changes
3. undo changes
4. attempt using ctrl+shift+z to redo

OBSERVED RESULT
before being able to press the Z key to redo, the colorize tool interprets ctrl+shift as "temporarily toggle the 'edit key strokes' checkbox", inserting a "property change" undo item and pruning the undo stack.

EXPECTED RESULT
ctrl+shift should not have any action on its own (let alone one which affects the undo stack).
otherwise, this should be configureable behavior, and not seemingly hard-coded