Created attachment 103573 [details] Screenshot displaying bug If the menubar is not the left-most widget in the panel, it causes the widget to fail to read where the mouse is properly. For example, if I click on "File" the file menu will drop, but then immediately switch over to "View". To access anything in the "File" menu you have to click on one of the buttons, then move over left of "File" at which point it works. I'm attaching a screenshot of the behavior. In my screenshot, it is shifted over by another applet (it's bugged so you can't see it), and it does this with other applets, or even just a spacer.
Should be fixed in 5.9 final by https://cgit.kde.org/plasma-workspace.git/commit/?id=083396bfd8495115fafbae3f9e475668149d8aab
Okay so I'm running the official 5.9.0 release but the bug is still affecting me. I run Gentoo, so I was able to look at the source for my specific version and can verify that the commit you posted is there.
KDE Neon User Edition with Plasma 5.9 final here. This bug affects me too.
openSUSE Tumbleweed with Plasma 5.9 final. Same problem here
I'm on OpenSUSE TW with 5.9 final, and I am also running into this bug.
Ah, now I understand. You are refering to when you move your mouse between items, not when clicking them for the first time. I just fixed that for 5.9.1. *** This bug has been marked as a duplicate of bug 375535 ***