Still happening in 392
Message was:
Cannot focus invisible or disabled window
The exact circumstances -- I am trying to go back to the previously selected drive for that tab, using the drive combo box. The drive letter is already shown but I use the drop-down and select it. I get the unhelpful message. I choose a different drive, it's all right.
It doesn't happen every time. It just won't change unless I choose a different drive than the one already shown in the drive combo box.
Edited to add:
I am FTP-ing a lot, so I get more chances to make trouble

Now it won't stop doing it. It has changed drives, but every time I change again it complains, no matter which drive. It changes the drive, but the message comes up every time.
Okay, after about the eighth time it settled down
Edited to add:
It just did it in a different tab, I switched from the one I had been FTP-ing in to change drives in another (same side, but different tab).
I think I will go back to using the drive bar for a while, and see if there is any problem that way. I prefer the drive bar in a lot of ways, but it bothers me when I accidentally hover over the floppy drive icon and the drive makes noise. :p
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Also I am having a hard time logging in to this forum. It works best when I use the Reply button. I would rather log in and then edit an older post, but nothing happens when I log in. So I hit the reply button and log in and then use the links on top to go back around and get in to edit. If that doesn't make sense, don't worry about it. I get here one way or another.