Windows 8 - application appears and disappears on taskbar

Here’s an odd question for people: is there a legitimate reason why a program would show up on my taskbar and disappear in a split second? I only ever see it in my peripheral vision - it never stays up long enough to see what it says.

As far as I can recall, it has only ever happened while I’m using Firefox.

Any ideas?

Could be some add-on/plug-in that requires to start into the front and then disappears into the background.
Might be your antivirus, popup blocker etc software.

Thank you for your input, Doughbag. Those are certainly possibilities.

Maybe you’re visiting a site in Firefox that opens a new Firefox popup window, then immediately closes it? (Some websites do this.)

Do you have the taskbar configured to show a new icon for each of a program’s windows, or the default where it combines them all into one icon? Try changing that setting (on the taskbar’s Properties page) and see if the issue goes away.

It could also be an automatic updater for drivers or some such - I have an HP machine and it does stuff like this - and every now and again, the transiently-visible update program blossoms into a popup asking me if I want to apply some updates it found.

I was finally able to get a proper look at it - it was the HP Support Assistant.