Could you test the following setting if you haven't already tried this?

There is a new-ish feature when you restore a previous session to wait until you click a tab before loading the page. Maybe this affects windows as well?

This option is set here:

orange Firefox button or classic Tools menu > Options > General

Right below "Use my windows and tabs from last time" there is a checkbox you can uncheck labeled "Don't load tabs until selected".

Does that make any difference?

Actually that just made it worse! Haha

I have now 25 windows open when I restarted and only two had the title.

Did you actually have 25 windows open in your previous session?

Firefox stores session information in a file named sessionstore.js. Perhaps that file has become corrupted? To start clean -- naturally this will purge your last session -- you can rename that file and let Firefox create a new one.

To access your current settings folder (your active Firefox profile folder), use

Help > Troubleshooting Information > Show Folder

Copy all the sessionstore... files to a save location for future reference if necessary.

Switch back to Firefox and use Exit to fully close the browser.

In the Windows Explorer window, rename sessionstore.js to have a different extension, such as sessionstore.js.bak.

If you want to salvage URLs from your old sessionstore files, the format is somewhat challenging to read, but if you open it in a text editor that is aware of URLs, then they will be underlined at least.

I actually did have 25 windows open(working on a paper for grad school); I did change the sessonstore.js to sessionstore.js.bak and exited Firefox. It did make a new sessionstore.js as I restarted it, but now there is not a single window had a title on it this time.

Weird, huh?

Hmmm, I assumed you would just have 1 new window if you renamed your sessionstore.js file. Somehow it found your old session anyway? Hopefully someone more knowledgeable about this area of Firefox can pitch in.

Meanwhile, at the time that the Task Bar doesn't show the true title, does the actual window display the true title, or are those windows still not loading, even after turning off the deferred loading feature?

I wonder whether any of your add-ons could be interfering with windows loading? A standard diagnostic for that is to try Firefox's Safe Mode.

First, I recommend backing up your Firefox settings in case something goes wrong. See Back up and restore information in Firefox profiles. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

Next, restart Firefox in Firefox's Safe Mode (Diagnose Firefox issues using Troubleshoot Mode) using

Help > Restart with Add-ons Disabled

In the Safe Mode dialog, do not check any boxes, just click "Continue in Safe Mode."

Still slow loading? Better?

When I renamed the file and started up firefox it popped up to restore my previous session-go figure.

The windows show up themselves with the pages fully loaded, but I have to click on each window to see what site that popped up(I used to just be able to see the title right when I clicked from the taskbar)...and this was after turning off that feature.

I appreciate the help you gave me anyway. :)

Let me try that first...

In safe mode right now and it works like a charm! All 25 windows popped up the titles....

SO now the question is what add-on is causing this?

Tough question to answer. Usually it's best to disable all extensions (that's one of the options in the Safe Mode dialog, or you can do it manually) and see whether that fixes it. Then reenable the most essential ones as a first group, restart, see whether it's still good, then try the other ones in batches.

Well, at least we got to the root of the problem and now it's just some "Trial and error" .

Thanks for your help! I really appreciate it! :)

EDIT: It was "DivX Plus Web Player HTML5" that was doing it.