A bit later I also wanted to try out the !ToggleMouseActionGroup / !DisableMouseActionGroup / !EnableMouseActionGroup bangs. None of them worked. I read the documentation, but had no luck, couldn't get them to work.
Finally I discovered the cause: these bangs, despite of what the help says, require the parameters in revers order. The order of the parameters have to be:
Meter, MouseAction(s)for the bangs related to a single meter
MouseAction(s), Groupfor bangs related to a group.
[!ToggleMouseActionGroup Buttons "LeftMouseUpAction"], but this does:
[!ToggleMouseActionGroup "LeftMouseUpAction" Buttons]. The same way, the
[!ToggleMouseAction Meter1 "LeftMouseUpAction"]bangs does work (Meter1 is a meter belonging to the Buttons group).
Looks extremely weird to have a such difference between the same bangs related to groups, against those related to one meter. Would be good if this would be fixed, but if it can't be, at least the documentation should have to be.