Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem,

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

While you are in Troubleshoot(Safe) mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}

That looks like tooltips and you normally see a tooltip if you hover specific elements on a page. If you move the mouse away from this element then the tooltip should close. You can move the mouse around to see what elements trigger a tooltip and then try to avoid these areas.

That fancy tooltip also will appear if you tab through the links in the document to select the time. (It might be easier to double-click a word in the post and then Shift+Tab to tab backwards to the link.)

On my Firefox, when a link is selected, there is a heavy blue box around it. I don't see that on yours, so maybe that isn't why the tooltip is appearing.

It's curious that there appear to be three extra buttons at the upper right of your post, but maybe I just don't use Facebook enough to see those.

None of the three above replies were even close. Never saw tooltips before and these boxes have nothing to do with where the cursor is.

Safe mode did not really help either, but it gave me a clue. Several add-ons were disabled with the upgrade. I removed them and reinstalled them. That seems to have cleared up the problem.

Thank you for the suggestions, though.

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems.