Bug 498574

SUMMARY
When I placed my clips in the timeline and already have a default Transform effect on the clip (no change to Transform yet) and I use the Slip Tool to move the clip around, the 1st frame of the Transform effect is lost, which is somehow logic because it is move to the left, but it is not possible to add a new 1st keyframe to the clip again. Workaround is to delete Transform and re-add it again to have a working 1st keyframe. Maybe also an issue with other effects which are keyframeable.

STEPS TO REPRODUCE
1. Add video clip to project bin and timeline
2. reduce the length of the clip in the timeline to be able to use the Slip Tool in step 4.
3. Add a Transform effect to the clip
4. use the Slip Tool and move the clip to the left
5. check if the Transform effects 1st keyframe is usable / available

OBSERVED RESULT
* after using the Slip Tool the 1st keyframe is "broken" while it is logical that they 1st keyframe was moved left, but it is annoying to not be able to add a new 1st keyframe
* workaround is to remove and re-add Transform effect agin

EXPECTED RESULT
* when releasing the Slip Tool a new 1st Keyframe of the already existing effects could be useful

SOFTWARE/OS VERSIONS
Operating System: Debian GNU/Linux 12
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.0-27-amd64 (64-bit)
Graphics Platform: offscreen
Processors: 12 × 13th Gen Intel® Core™ i7-1370P
Memory: 62.5 GiB of RAM
Graphics Processor: Mesa Intel® Graphics