Outline missing on some pools and lanes in collaboration diagram

[zajonc]

The black outline to some of the pools and lanes are missing in my collaboration diagrams. That means I can't see the lane boundaries. In some cases the pool is also missing its outline, but that is less important.
Anybody else run into this?
Any ideas?
These are mostly processes that were created in version 14 and are now being edited in version 15.

[zajonc]

This is fixed in version 1511.