We have a problem with the constraints "must ...".
Currently it is possible to define 2 tasks one before the other and add a must start on constraint to the successor. The problem is only the constraint "must start" is respected.
We don't understand why no alert popup appear to the user to prevent the problem.
You can replicate the problem with the online example : https://www.bryntum.com/examples/gantt-for-extjs/kitchensink/#examples/constraints
1. remove the constraint on the first task "Constrained Task"
2. change the constraint on the second task to "must start on"
3. drag and drop the "Constrained Task" to a later date than the constraint.
4. no alert to prevent user than predecessor/successor constraint can't be respected
It should not be possible to have an arrow that goes back to the gantt (see enclosure).
Thanks again for your responsiveness and your help.
Note: We have the same problem in our project and we have set these variables
scheduleByConstraints: true,
checkDependencyConstraint: true,
checkPotentialConflictConstraint: true