pop-up windows all the time in Firefox, Stretch

[Anil Duggirala]

hello,
Ever since I moved to Stretch I have had pop-up windows popping up all
the time (clicking on various items on various types of pages). I am
posting here, since this is only happening in my Debian installation.
Was anything changed in the default configuration of Firefox. It feels
like Windows with all of these pop-ups, this is the first time I
experience anything like this in a linux installation.
thanks,