BWD PopDrop in Foundry problem

Hi!

When putting a PopDrop Menu Stack inside of a Foundry2 project, I get a strange little blue line beside the burger icon when clicking. This happens in preview mode and in a browser.
Also tried with an otherwise empty project…
When doing the same in Source, everything works as intended.

Could this be a bug or am I doing something wrong? Any ideas?

Thanks and cheers,

Markus