First, my problem is occurring on personal web page projects I work on. Every file is saved on and accessed from my local hard drive. My projects involve two frames...left frame is table of contents, right frame is the "main frame". I hide the table of contents until the mouse goes over to a certain part of the screen...when this happens, the contents frame "pops out". When the mouse leaves the contents frame, the frame hides itself again. Since the last Firefox update, (July 18 2019, I believe), the pop-out / hide functions aren't working. The frames still load in, but they won't pop out or hide when they're supposed to. They stay at whatever size I resize the frame to. In addition to this, my personal project pages are no longer loading in the fonts they are supposed to. Everything seems to be defaulting to the system (or Firefox) standard. More Information: The pop-out / hide functions only seemed to ever work with Firefox. I never could get it to work with Opera / Chrome / IE. This is the main reason I stuck with Firefox for so long. Is this an error that is going to be fixed, or a byproduct of a change that's been made that I'm just going to have to live with? I can provide more information if needed.