Sync Lock Timeline
Useful for editing music videos where there are many video tracks that must remain in sync.
Sync Lock would lock the horizontal position of clips on the timeline, but still allow them to be selected and edited like normal. Any "ripple" type of edit would be blocked completely.
James Clark commented
Hey man. I just posted a suggestion regarding sync locks as well, although mine was about a way to improve their current implementation. Are you requesting that they exist at all, or have I misunderstood?
I ask because if you're just suggesting that Premiere have sync locks then I have good news for you. Premiere has sync locks already. If you look at the left side of the time line where you can see the track numbers written, you'll notice that to the right of the track number icon, and to the left of the eyeball icon there's an icon represented as two rectangles and a conjoining line shaped a bit like a backwards 'c'.
Those are Premiere's sync locks, if you click on one of those for a given track, a diagonal line will appear through the icon indicating that sync will be disabled for that track allowing you to make cuts with rippling effects like insert or extract on other tracks safely without affecting the track for whom sync lock is disabled. You can also still make cuts to that track, if you've selected it as the active track, which is where it differs from simply 'locking' the track.
My problem with the sync locks though, is that they affect synchronisation of edits you make only uni-directionally; they prevent actions you do to OTHER tracks affecting specific ones you've selected, but they don't prevent actions you perform on the track itself from affecting others. Imagine you're cutting a music video and wisely turn off sync lock for the music track so you can make whatever rippling cuts to the video you like without affecting the music. Everything's going great and just like you wanted, except now imagine you want to make a change to the music track without affecting all the other tracks. You'd think since you'd already disabled sync locks on that track, that it would mean nothing on that track is synchronised with other tracks, but in fact if you were to make an insert edit on the music track, that insert would place a gap of the same length on all the OTHER tracks besides the music as well with the way sync locks currently work. I use music video as an example because that's something I know you're particularly familiar with but actually it's not a situation where my gripe with sync locks matters much because you'd rarely if ever be making changes to the music track that have rippling effects, you'd likely only be altering things like volume. However in other situations like documentary, with a lot of overlay and interview these uni-drectional rather than bi-directional sync locks are a pain in the bum. Other platforms will treat sync locks bi-directionally which makes more sense.
Hopefully for you though, your issue is solved because in fact there ARE sync locks. Hope that makes you happy.