From user report (but I've had this myself):
|HotCat is a popular gadget and any conflict with it should be avoided. For|
|example, use VisualEditor on [[User:This, that and the other/sandbox/Schfoof]]|
|with HotCat enabled. The HotCat bar appears in the wrong place. (It probably|
|shouldn't appear at all.)|
|The conflict now appears to be fixed... very strange.|
Given that it appears and also doesn't appear between refreshes - i.e., on the same page with the same version of the VE and HC code bases in the same accounts in the same browsers - I'm assuming it's some sort of race-condition, but I'm not sure.