Lag adding first transition
There is a lag of about 3 to 5 seconds when adding the first transition to a clip, afterwards it works quickly.
1- Add clip to timeline. 1- Click on the square in the corner of the clip to add a transition. 1- 5 second lag then the transition rectangle appears.
Here you can find the Heaptrack info: https://share.kde.org/s/qqGPAcCnnyFEca7