Undo trim clip in may shift clips bug hasn't been completely fixed

Original bug was only partially fixed a few months ago, and there is still a way to produce this same bug with some additional actions.

  1. On the timeline, arrange 3 clips so that there is space between A and B and no space between B and C.
  2. Trim clip B’s In point toward A so that it reaches the Out ponit of clip A.
  3. Undo.
  4. Redo.
  5. Undo again.
  6. Check the In point, Out point, and duration of clip C. B’s properties are copied to C.
  7. Clip B also has the duration of clip B before trimming plus the length of the trimming.

Additional notes:
A. Tested on Windows 10
B. Tested on two of my PCs that have different CPUs.

Thank you for the excellent report. This issue is fixed for the next release (probably 21.08)