Improve Nested Group Handling: Selecting, Moving, and Resizing

[Tojioo]

This is somewhat a follow-up to this: @WanderFox #4874

It seems that groups still can't be resized from any corner (same with nodes, but that's fine tbh). While that's not my main point, any plans on making this possible in the future?

Now to the main reason for this; What has been bothering me for quite a while now it the fact that whenever there are groups within another group, its not possible to select and/or resize them.

While it is possible to select the group by holding ctrl, moving it isn't possible unless the content of said group is selected and used to move it by proxy.

As to resizing, I haven't figured out any workaround. The only way to resize nested groups is to either resize the main group, or to move them outside of the main group (which can only be done by using the previously mentioned workaround).

Please let nested groups behave in a way that makes them selectable, moveable, and most of all resizable without having to conjure up voodoo spells :D