PROBLEM:
You have created or edited a group, but when you go to finish the group you can't find the menu panel with the green tick.
SOLUTION:
Use keyboard shortcut to finish the group:
FG = Finish Group
CG = Cancel Group
To restore the group panel try going to the View Tab, then User Interface.
Check and then Uncheck (or vice versa) the Recent Files option.
If you see the group panel in the drawing area (i.e. not in menu ribbon), drag it up to the ribbon. This should stop it happening again.