Allow custom actions to see the current keyboard modifiers #4483
Description
When writing custom actions, I'd like them to be able to tell if, say, the Alt key was pressed while the action was invoked. For example, maybe the action normally puts up a prompt to select some values, but if Alt is held, it reuses the values from the previous time without prompting.
It would also be nice if their name could automatically update based on the current modifiers. For example, in the above case, the action name should be along the lines of "Do Something…" (note the ellipsis) when Alt is not held, but "Do Something" or "Repeat Something" when Alt is held. This would need to be something in the action object, as it affects the name seen before invoking the action.