Broken: 2.79, 2.8x
Short description of error
When using linked objects, all the Group commands [Remove From Group / Remove From All Groups / Add Selected To Active Group / Remove Selected From Active Group] except [Create New Group (Ctrl G)], do nothing
Exact steps for others to reproduce the error
In my particular usage, I link a scene from one file into my main scene, afterwards I create a [New scene with Link Objects] from the Linked scene.
I can Create Groups by selected objects, and I can remove the group from the object in the Object Properties tab but the only way to remove multiple groups is through python script or deleting the group itself.