Created attachment 6701 a video to illustrate the described behaviour xfce4-popup-whiskermenu 1.5.1 It's the version of XFCE that ships with Ubuntu 16.04 LTS. There is an XFCE meta package. Apt says it is version 4.12.2 (xenial). When I open up whisker menu by keyboard shortuct and start typing it limits the shown items to those matching my search. The first item in the list of results is selected (unless I select another one). This is the behaviour I expect. The problem arises when the mouse cursor is positioned over the shown entries while I type. Immediately after I stop typing the selection jumps to the entry under the mouse cursor. In consequence I sometimes start up the wrong application by accident because I am not aware all the time of whether the cursor is positioned on the menu or not. There is a small delay before the other entry gets selected. But it's way to short. When I type to search and than stop for a second to contemplate and than hit enter, the selection might have changed or not, solely depending on where the cursor is. I think, more delay would help, but it wouldn't solve the problem completely. I'd rather have this change of focus triggered by cursor movement. I've attached a video that illustrates the problem. Please note the the selection jumps to the cursor on its own, without a mouse click.
There is no delay, at least no delay programmed into Whisker Menu. That would be silly. I don't tell it to change selection to the cursor during searches. What is happening is an unforeseen interaction between my telling GTK to select following the mouse cursor, and then my telling GTK to automatically select the first search result. Solution: there is none that I can think of. Sorry. My advice is to not do that. Just move your mouse off of the menu. As an aside, this bug doesn't happen for me. I'm using Arch Linux and not Ubuntu, so that may be why. When I search with my mouse hovering over the menu, it keeps the selection on the first entry no matter how long I wait during typing.