No matter what part of the menu (File, Edit,View, . . . ,Help) I left-click on, the box opens, then closes again, immediately. Preferences works, because it opens a new tab, but Options is also useless, opening then closing immediately. Doesn't matter if I click quickly, or hold down the left button. It just closes within a few milliseconds. I looked at reloading it, but that requires using the Options menu, so no good. I'm running Linux Mint 17.3. It is Firefox 60.0 64-bit. I can't imagine what image to include, since I imagine capturing one of those very briefly open boxes would be next to impossible to capture open, and you'd just have to take my word for it that it closes really fast anyway. I just added a new logitech wireless KM combination, but this problem was occurring before that, on this computer, I believe. The problem does not occur in LibreOffice Writer, or in the Linux terminal, or when right clicking any icon anywhere to check or change properties, etc. Only in Firefox and only on this computer. Is there some way to fix this?