Task Manager shows 5 Firefox on only one Firefox window.

Please be relevant, helpful & nice!

Curious situation.  So I googled it.
Apparently one TM entry is "UI" (User Interface) -
and the other four are "content".
But an article showed how to get rid of one of them.
Now this is discussion.  Not recommendation.

One brings up another Firefox window -
and types "about:config" in its URL box and hit Enter.
There'll be some kind of advisory - one OK's that.
And then one is on a gigantic settings page for Firefox.
But its easy in this case. 

In the search box there - one just types what one wants.
On this its:  "dom.ipc.processCount" 
The quote marks not needed.  Hit Enter.
The entry will come up. Right-click it for "Modify".
I changed it from "4" to "1".  Hit OK.
X'd out of that window.

Is that what stopped the freezing?  I can't be sure of that.
Or even that it helped at all.  Or isn't now a time bomb.
There's lots of things like that - with a computer.
And I haven't tried modifying that entry to "0" yet. 
Could that Crash Firefox?  If it did - no big deal.
Firefox is an easy reinstall.  Under 10 minutes.
Under 5 if you're fast.  Could even clean it up!