Timeline: remove clip you can move the whole Kdenlive window by grab the playhead

Summary
I found a strange behavior with the playhead and the timeline which I can demonstrate on Windows more clear then on Linux.
Could it be that the clips/proxy and effects are not proper scaled down in the timeline for playback.

STEPS TO REPRODUCE

1. Kdenlive new started -> playhead on timeline work as expected
2. Add a clip to the timeline -> playhead need some time to react instead a blue line appears on the timeline header -> solved with https://invent.kde.org/kde/kdenlive/commit/1cf58f62e8c3cc5efe90b9b36605f6e52debe134
3. Delete the clip -> playhead doesn’t work anymore. Instead you can move the whole Kdenlive window by grab the playhead. Playhead work only with the arrow key.
4. Add a clip again to the timeline -> playhead moves only when you select the clip or wait some time. -> solved with https://invent.kde.org/kde/kdenlive/commit/1cf58f62e8c3cc5efe90b9b36605f6e52debe134

OBSERVED RESULT
Slow and strange behavior of the playhead and timeline

EXPECTED RESULT
Playhead and timeline react without time lag and we can’t move the whole Kdenlive window.

Timeline-playhead-lag The gdb log (probably not so helpful): Timeline-playhead-lag_gdb-log.txt

See here with a youtube video for Linux: https://forum.kde.org/viewtopic.php?f=265&t=160833
see here changing the porject settings to speed-up the playback: https://bugs.kde.org/show_bug.cgi?id=369080