Mostly for timing marks. if I wanted to clear all the timing intervals from the sequence, or insert multiple timing intervals. you highlight the portion of the waveform (in this case it would be the entire waveform) and select remove intervals from selected range.
Unless there is a way to add/delete timing intervals for the entire sequence other than starting over or to have multiple timing intervals like in LOR.
My way of doing multiple timing marks is to create the marks say at .10 intervals, do some sequencing, than delete them and add another set of marks say at .05 to do some fine tuning.
Laugh if you must, but I'm still a grid sequencer for the time being.