Store map name on which a Toolbar Button has been pressed

It would sometimes be useful to know in which Map Window a Button was last pressed. For example, I have a GKC button cloned in several windows that sends a command to a service piece hidden on the main board. That piece then does stuff affecting the window where the button was pressed.

In v3.5 and earlier, this would require the GKC button to be send a different Global Key Command in each window and for that command (on the piece) to first set the window to be targeted. Or for a clone of the service piece to be in each window.

Perhaps the window name could be stored in a special module-level property when a button is pressed ?
e.g. ButtonMapName

I think this would need to be for each of Global Key Command, Multi-Action Button and Action Button components, as these are the button components that can result ultimately in a piece receiving a command.

Making the button press the driver rather than the GKC avoids the complication of what would happen if the compound action involved other GKCs in other windows beyond the one in focus.