This was determined to be a limitation where the tasks cannot be grabbed when task time short time (15 mins or less )
This is generally okay but some tasks which are around 15 minutes have very little “clickable” area to drag. that time we have issue.
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Seems to work just fine for me, how do you reproduce this here? https://bryntum.com/examples/scheduler/basic/
Yes please read the upgrade guides in the documentation:
https://bryntum.com/docs/scheduler/#guides/upgrades/4.1.0.md