I have never heard of this exact problem. Did this behavior start with a particular version of TenFourFox or has it always been this way? Are you running 10.4.11 or a previous 10.4 version? Can you do the Apple Hardware Test (in's on the install DVD/CD for that Mac), if available? What happens when you take, eg., a TextEdit window, drag it over the 'frozen' TenFourFox window and wiggle it a bit? Does it leave any residue? Does the browser window become responsive when it's put in the foreground again?
I'm running 10.4.11 and I've noticed it in TFF for several versions now. It's not really a big deal because I can always quit and restore session if I forget to switch programs before sleeping the computer. I have seen it on the laptop screen, but it's definitely repeatable on an external screen at 1920x1200. The computer passes the hardware test and my previous 12" powerbook did the same thing (1.33GHz). My current powerbook has a drive cloned from the other one. I've considered reinstalling everything, but I was wondering if anyone else could reproduce this before I go to the trouble.
The locked up window behaves ok within the OS. I can move it, resize it, switch to another program and back, and the contents of the TFF window are not corrupted. If I resize the window smaller the scroll bar on the right does not redraw. With activity monitor going, TFF is not pegging the CPU or swapping in the locked up condition. The menu bar still works, and if I 'Quit TenFourFox' the 'Do you want TenFourFox to save your tabs...' box pops up but the default option button does not show darker than the other buttons, as if that popup window is also not updating. But I can still click 'Save and Quit' and it will gracefully close down TFF.
Again, this is not much of a problem for me. I wanted to document it and maybe see if any other 12" powerbook people had noticed it.
I routinely sleep TenFourFox on both a 1GHz iMac G4 and my 12" 1.33GHz iBook G4 (both running 10.4.11) and I've never seen this. The iBook G4 is Radeon, but the iMac is Nvidia, so I would expect it to reproduce there if it were a problem with the Tiger Nvidia drivers.