Edit Item window will not resize

Yes, that type of window (I think all of the list edit windows) can't be resized. It can be maximized, but not resized. If you're in single window mode, it'll be maximized automatically, as will almost all windows.

Perhaps if you post a screenshot that will help others understand what you're referring to.

I just wanted to let you know that you're not going crazy.  I can confirm that something happened very recently that made it impossible to resize the edit window.  It happened first on my main desktop machine, but was still working as expected on my server machine.  I then went back to my main desktop and did a repair install, and that fixed it for a while.  But as you know, QuickBooks constantly wants to update itself, and following the next update, it again became impossible to resize the window.  The next time the server machine got an update, it too was afflicted.

I tried to get help via chat, but it seemed apparent that the agent had never actually done any work with QuickBooks.  He dug up some ancient articles that don't even describe current versions of Windows or QuickBooks.  There was conversation about Windows compatibility mode, which is something that became irrelevant as soon as a QuickBooks development caught up with Windows.  I think that goes back to Windows XP.  I saw those same articles a very long time ago.  And yet everyone wants to dredge them up, as if something that didn't work 20 years ago would suddenly start working now.

No, somewhere along the way, an update broke the software and the QuickBooks guys have not been able/willing to receive input from real-world users.  It's a big problem, but I don't know how to talk to anyone who cares.