The other way to really see how a groove is changing your clip is to use the Commit button:
In the case of a MIDI clip, this will simply move the notes in your clip to the locations specified by the groove, much the way Live’s Quantize function moves notes to conform to a grid. For audio clips, Commit will cause new Warp Markers to be placed, and those markers moved to make the clip conform to the groove.
Not only does this make it really clear how the timing of the clip is being changed, it leaves you free to make individual adjustments if a particular note doesn’t sound quite right.
In either case, the clip’s Groove will be set back to None. Since the changes have been made directly to the clip, a groove setting is no longer necessary.