Unless I'm mistaken, for years I've done the following to trim the head of a clip:
With a clip on the timeline selected, press ctrl-K to insert a cut.
Hit shift-delete to ripple delete the section to the left of the playhead
But today I've noticed that PPro seems to auto-select whichever clip is under the playhead/CTI, which means that shift-deleting removes the clip after my cut, not the one before. Why does PPro auto-select clips now? Is that something new? Have I inadvertently activated something? It's REALLY annoying!
SOLUTION: After a hunt around, I found that I must have somehow inadvertently turned on Sequence > Selection Follows Playhead. I won't be making that mistake ever again!