Unfortunately TGUI does not support horizontal scrolling in TextBox, only vertical. Although I don't think SFGUI or ImGUI have support for it either. For ImGUI there does seems to be
an open issue for it with some hacky partially working code from 2015 though.
0.74 or 0.8
If you want to use TGUI then 0.7.4 is for when you want to be certain that my future patches don't break your code, 0.8-dev if you want to have the latest stuff but find it acceptable to from time to time make changes in your code when updating to a newer revision. The layout system is currently the only part that is still planned to get an overhaul in 0.8-dev in a few months, although there probably will be some other major changes that I will come up with afterwards.
shh, texus doesn't know yet
He does now