Clip Group Timebase Format
Clip groups are created in the same timebase format (samples or ticks) as the tracks on which they are created. Multitrack clip groups can include both sample-based and tick-based tracks.
Audio Clip Group icon on an audio track
MIDI Clip Group icon on a MIDI track

Clip groups can be created from empty selections. This can be useful when working in Shuffle mode to preserve the gaps between clips.