Full Chat control GUI https://pastebin.com/RGM1cRj0
Edit:
I accidently forgot some lines! use the new one ^^^
I know for clearing chat, the "loop 6000" part is crazy and lags a server, but I did it because some clients such as lunar, allows you so you can scroll up thousands of texts. I guess looping it 6000 times is big enough where you can't scroll all the way to the top when the chat was cleared.
If you have any issues, please tell me so I can fix it!