I did not see any problem mentioned about the ETW when I did a search, so I will mention it now.
When I close the ETW, I cannot get it open again in-game. Options-->Actions-->Extended Target only works to close the window...it will not open it. Also gave the command a hotkey using Options-->Keys-->Target(category)-->Extended Target Window Toggle...still won't open the ETW.
Only way I can get it open is to shutdown/restart the client.
Not sure if this can be server-related though...isn't window control done by the client?