I am working on a CMake project on the macOS version of Qt Creator 4.10.0-rc1. I continue to have popup menus be "abandoned" – i.e. they are left up on the top layer and will not go away until I close Qt Creator completely and then reopen it. Attached you'll find a screen shot of the abandoned popups overlying the browser where I am writing this bug report.
These popups get abandoned whether I am using them in Projects or in the drop down bar above the Edit panes.
There are several executable targets of my CMake project.
My version of macOS is 10.14.5 (Mojave)