The only keys we can assign to any custom actions are ESC and ENTER, and those generally only work if the window is on top. Other windows that make use of those keys will intercept the input if on top.
It is possible to cludge up a macro and custom window combo that will allow you to activate stuff via-hotkey, but its prety involved. Basically here's what you do...
Create a custom window with an OnShow script that activates your widget.
Include in that script a line to automatically close the window (so you never actually see the window).
Now in-game, create a macro that opens that window, something like /show_window MainHud.ShrinkMap.
The Macro can be assigned to any hotkey. All it does is opens the custom window. The custom window script then activates your widget and hides itself
