User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20161115182233 Steps to reproduce: Open Firefox menu Click to open a subview, such as history or help Click to exit the subview back to the main menu Alternatively: Open the Control Center panel in Firefox Click to open a subview Click to exit the subview back to Control Center Actual results: Text in main menu disappears while subview is animating in and out Expected results: Text stays visible.

I think it's a dupe of bug 1306670 which should be fixed in a next Beta build. Reopen it if that's not after bug 1306670 landed in Beta.