I don't plan on picking up studio, but I wouldn't be above working with somebody who has it to figure out the necessary changes. I don't know what changes were made from 8.1 -> studio, but the windows, drop menus, and some event control functions rely on surfaces and custom drawing, so it may be that it requires a total re-write to switch over in which case I probably wouldn't be able to without having studio myself.
If anyone has studio and would want to work with me on it please PM me, otherwise no, I probably won't port it over, unfortunately. Theoretically almost everything should work the way it is now since most of it is just mouse checking and drawing, just probably not the windows, drop menus, and some GW_Control_ functions, all of which can be deleted from the script package. For a temporary solution I can upload a light version with these things removed, but again, I would need someone with studio to test it for me.
I have Studio, hence why I asked, guess I should've said that huh :^). Anyways, it seems to work OK, except for the following so far:
In show_menu_ext, line 26 is an obsolete function (variable_global_exists)
In GW_Init, line 31 obsolete function (object_add)
In o_GW_Window step event action 1 line 47, obsolete function (window_mouse_set)
I'm still learning studio myself, haven't had much time to buckle down to see if these functions were replaced with others or will have to be custom. So far though, that's all it errors out on. That's a direct import of the Game Widgets GM8.1 into Studio.