Hi Behnam,
We have created a sample to achieve your requirement. By
configuring boundary constraints as 'Diagram' in pageSettings, you can restrict
swimlane dragging in the negative region. By default, the boundary constraints
are set to "Infinity". Please find the sample below for your
reference.
Sample: 9mabv2
(forked) - StackBlitz
Regards,
Sivaranjith.