There may be a way to do this already and I just don't know it.
I mix a lot of music where it was not originally recorded at the tempo it is performed. Usually around the time I'm wanting to use tempo sync on an effect I realize I need to set the tempo for the song.
At that point, I have to go through ever track and clip and manually set the timebase to Absolute or my clips will jump and my envelopes will go off when I change the project tempo.
Quick Grouping does not seem to work for this setting, so I can't just select all tracks and ctrl+click. I have to do every track, bus and set of clips separately.
A way to flip this globally would really help.