https://bugs.winehq.org/show_bug.cgi?id=39765
--- Comment #4 from louie.caulfield@gmail.com --- (In reply to louie.caulfield from comment #3)
I was able to reproduce this bug with 2.0-rc5 on Linux Mint and macOS Sierra.
Not accurately enough: I think the same bug occurs (at least the same behavior), but with a different reproduction scenario: basically closing any floating dialog results in this error.
i.e.: undock/float the projects view, by dragging it away by its blue title bar. then close it.