Well, managed to get it working on my end but not sure if it will solve the problem if the code I removed is needed for it to work in other conditions.
In the nUI_ChatFrame.lua file in nUI/Integration folder. Lines around 345 the following were my changes:
Code:
elseif event == "UPDATE_CHAT_WINDOWS" then
reparentChatFrame();
-- elseif event == "UPDATE_CHAT_WINDOWS"
-- or event == "UPDATE_FLOATING_CHAT_WINDOWS"
-- or event == "BN_CHAT_CHANNEL_CREATE_SUCCEEDED" then
-- reparentChatFrame();
I don't use Battlenet so I am not sure how the BN_CHAT event will be affected here. Similarly I have yet to find a use for the UPDATE_FLOATING event as I had been using that test in my own addons and getting similar problems so simply removed the test.
Here's a final screenshot, taken after another new tab was created and logged out to login screen just as before, and then logging back in.