About the buttons, the problem comes from the use of <br> inside the text string.
This cause a problem in the global HTML code.
To have the expected effect, replace <br> with its equivalent
So your lines become :
A$ = A$ + button$("<b><big>Quick set to 5 deg.</big><b/>", Qset5, "but1")
A$ = A$ + button$("<b><big>Quick set to 15 deg.</big><b/>", Qset15, "but2")
Thanks cicciocb