That is not a built-in feature of Firefox. Do you have an add-on such as Fox Splitter installed? That one appears to do what you are describing.

You are right, Tony, thank you very much. I must have fumbled my way on to the splitter, but there it was. Not fully enabled, but causing a nuisance anyway. Not any more.

Thanks again,

Dan

Did U find a way to turn it off or uninstall it. I'd like to know how U did it.

While in Firefox, go to the "Tools" menu on top. Select "Add-ons" and see if you have the Fox Splitter. If so you can disable it. This is what worked for me.

Good Luck!

Thanks so much, I finally got it turned off. I thought it would be good for comparing things, especially in genealogy searches, and it was, but it sure is a pain because of accidentally touching it constantly!!! Would like to know if there is someone to contact to tell them to figure out a different way to do it because it can be useful, it is just too easy to do it accidentally, maybe it needs to be something in the toolbar.

Thanks again, I have shut it off, for good if it does not get fixed!