Tell Windows
 

Been using "Use Tell Windows" under UI options ever since playing. Fell asleep the other night while playing and came back and noticed I had about 40 windows open from tells over night. Closed out of all of them and now I notice tells are not creating a new window anymore. Have toggled on and off, rebooted client, reloaded UI. No change.
Any ideas?

Not sure but I would poke around your char@server_ui file for something that resembles tell windows x / y coordinates and try cutting them out.

One way to test would be to see if it works on another character.

All toons on all accounts not having issue. Only thing that happened was over spam one night when leaving client running. Ever since then issue has been happening.

bump, having the exact same issues

Go further, cut your character file out of the P99 folder, and set up from scratch again just as a trial to see if it's that.