Hello again!
Since my groupselection required changes to the file format to be
useful. I have now created a selection tool that selects all footprints
belonging on the same sheet or "deeper".
It also finds all nets that only have connections between components on
the same or deeper sheet and selects them.
It gives some functionality of the group selection idea and does not
break file format or any previous workflow.
Tested on linux, saw some strange right-click meny errors on windows,
but the functionality works there as well when using the shortcut key 'P'
Attaching patch
Video:
https://www.youtube.com/watch?v=DUskyc7t_HA&feature=youtu.be
- Kristoffer