Created attachment 8344461 [details] Console logs about Invalid display/context I regularly lock my Macbook Pro (Retina) using the Login Window while Firefox is running on my Dell Monitor (@1x). Many times after I login to my account after an extended period of time, the Firefox window is in a bad state with the previous width but minimum possible height (which mostly shows the titlebar). There are errors in the console which are attached but I don't have clear steps to reproduce since it doesn't happen if I just switch to the login screen for a few minutes. The other issue is that the window is sometimes unable to be resized vertically once in this state as the cursor doesn't change on the top/bottom window edges. If you minimize the window, it may not be possible to bring it back either (it will just show in the Window menu and mission control with only the title) but clicking on it will do nothing. Once you're in this state you have to restart the application to fix the problem (but the application will persist the window size which can then be fixed). I only started seeing this issue since upgrading to 10.9 although I skipped 10.8 on my work machine where I use the second display. I use TreeStyleTabs which could be a factor since it affects TabsInTitlebar. Snippets of some errors for SEO: * CGSCopyDisplayUUID: Invalid display * CGContextTranslateCTM: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
I use Mavericks fairly often on my Mac BookPro and have never seen this. We need STR before we can do anything here. > CGSCopyDisplayUUID: Invalid display > CGContextTranslateCTM: invalid context 0x0 Occasional "invalid context 0x0" errors have been around for years, and seem benign (see bug 930837 comment #6). But offhand I don't remember the "invalid display" error. These errors may or may not be relevant. As this keeps happening, please try to remember exactly what steps you took leading up to it. Try not using TreeStyleTabs for a while to see if that makes a difference. If it doesn't, try not using *any* extensions for a while.
Greetings. This sounds like an occurrence of a more general Mavericks problem, cf, this discussion: https://discussions.apple.com/thread/5516275. It affects a lot of applications, not just Firefox. I've been keeping careful notes of what's running when it happens to me. I thought for a while that it happened upon waking up after sleep or from screen lock (as suggested by MattN in the original post) but have seen it occur while I'm actively on the machine. It affects almost all applications I run, Apple as well as 3rd party, but the precise symptoms are different for different applications. So, not a Firefox bug. That said, if you great Mozilla developers have any ideas what might be causing this, please pass them along! Thanks, Nat