I have just upgraded to P&G Designer7 from Xara Xtreme 3.
I had problems ungrouping layers.
Maybe others have experienced the same difficulty.
So here is a partial solution.
Grouping layers is easy, of course.
Shortcut CTRL+G, moves all parts to just one layer.
Ungrouping is not so easy.
CTRL+U does NOT revert things to your previous multiple layers.
If you've saved saved your file, next time you have to tediously re-create all your previous layers from scratch.
CTRL+Z does revert to multiple layers, just as long as you haven't already saved the document.
You experts out there, if there is another easy solution, please let me know.