Lane removal leads to child lane overflowing the parent for some diagrams

[barmac]

          It seems there is some kind of rounding issue when deleting lanes that causes their boundaries to mismatch. This affects both horizontal and vertical lanes. This can probably be fixed in the future.

Originally posted by @sombrek in #2082 (comment)

Expected behavior

Child lane should be limited to the size of the parent lane.

[barmac]

More context:

Could you please share a diagram in which you got this result? I cannot reproduce it on my own.

Sure, it's test/spec/features/modeling/lanes/lanes.bpmn Open it via bpmn.io then delete lane c and lane b.

I cannot reproduce it with a newly created pool. Maybe it's because of the odd dimensions in that model.