Today I gave up on starting Firefox using the launcher because every time I moved the mouse pointer to the left edge of the screen, the launcher panel appeared, and immediately disappeared again (with the usual sliding motion). I never had the chance to move the pointer to the Firefox launcher button to activate it.
Now that I have Firefox running full-screen, when I move the pointer to the left edge, nothing happens. If I slide the pointer along the left edge, a gray fringe appears briefly, but no launcher panel.
But now that I am writing about it, and trying again, after a couple tries, the panel appears if I slide the pointer fast enough and also far enough. And now, once the panel shows, it does stay put until I move the pointer out of the launcher entirely. If I slide too slowly or to short a distance, at most I get the gray fringe described in the second paragraph.
I now also tried to minimize all windows to see if I got the behavior I described in the first paragraph, but no, I still have the behavior of the third paragraph.
This is not the first time I experience this. It's been countless times before. Quite possibly it happens only when I have just logged in. Yet I have not found anyone else asking about this.
The behavior described in the first paragraph is annoying, how can I fix it?