Is the bug reproduceable in Logitech-software (which is
also mozilla-based)?
If you mean the latest stand-alone one, no, they all appear.
In Firefox without Harmony Mod?
I think this problem appeared before I knew about the mod.
Maybe it's time to re-install firefox from scratch??? I am getting other weird things happening like layout problems. Sometimes a button will overlap text; that sort of thing. (Virus checked regularly.) I put them down to site incompatibilities.
Thanks