If many 3' ends are selected, or many 5' ends are selected (but not a mix), then right clicking and selecting "Add modification" should add to all of them at once.
If some ends are selected with a modification and add is chosen, just ignore those ends (i.e., don't edit them).
If many 3' ends are selected, or many 5' ends are selected (but not a mix), then right clicking and selecting "Add modification" should add to all of them at once.
If some ends are selected with a modification and add is chosen, just ignore those ends (i.e., don't edit them).