I have laptops, desktops, and tablets. Tablets Use Android and are not a problem. The other machines run either Windows 7 (especially the ones at work) and 8.1 (personal laptops.) Different makes and models, some with wireless mice, some with USB connected mice, the former mostly Logitech and the latter Dell. For the purposes of the rest of this description, note that the touchpads on the laptops behave the same as the mice. In all these machines, after recent upgrades (Firefox for certain, but probably other things), about 50%-75% of windows open without scroll bars and do not scroll with the mouse wheel. I can navigate with the keyboard arrows and the links in the windows respond to mouse clicks. I assume the windows are opening in some script or platform (Java?) that is different from what is used in other pages I navigate to and through. In most cases they are opened from links on other pages, although I have come up with some that appeared after entering the URL, and the presence of a tool bar is inconsistent. Sometimes there, sometimes not. Most of the times I am paying attention, the standard one is not there (i.e. no scroll bar/slider or standard toolbar. Looks like a popup with URL and search window and the bookmark toolbar.)

I am guessing this is a Firefox thing because Chrome works, but whether it is the browser itself or its interaction with Java, some setting, or what-have-you I don't know. Suggestions?