It would be great to be able to hold Opt/Alt while adding a Marker in order to have the marker added to _all_ selected tracks. Relatively frequently, I like to add a Marker on several tracks to be used as a Sync reference (on clips from different sources). This is especially true when I’ve got a stacked visual composite that also have timed keyframes; and when I have a bunch of sound effects that have been placed in a very exacting way (e.g. footsteps, gunshots, punches, etc.).