Current look of VSE timeline view strip transformation handles makes them
somewhat "too narrow", especially after recent changes that made them
more narrow than before (handle tweaking feature) and a strip visual change
that made strip outline not go outside of strip bounds. They are now just
2px wide, effectively.
This changes their look as outlined in #123332 design task:
- The inset dark line is no longer over the handles, but rather "inside"
of them (except when handles are semitransparent, i.e. for strips that
are not selected).
- The handles themselves have rounded corners.
Pull Request: https://projects.blender.org/blender/blender/pulls/123391
7e61f14a88