cat8
is what my (v19.0, windows) version looks like- there doesn't seem to be the option depicted in the tutorial and which I could swear I'd seen previously. I'm on Windows 10 and the latest update of Java etc.
Did something change or have I messed it up somehow?
Head tube extension
I assume you are referring to the tutorial at: bikecad.ca/tube_extension. Sometimes people miss the point mentioned at the 1:40 mark of the video regarding curved tubes.
If there is some other behaviour that seems different, please elaborate and I will have a look.
On another note, if you are running BikeCAD on a PC or a Mac, you do not actually need to have Java installed.