I found several bugs, one of which applies only when that listbox is disabled (some initialization is not getting run). Would you be willing to try a beta build with these fixes to see if that solves your issue? I should have one ready soon.
Sure, I'll try a beta whenever you're ready.
I have no idea what could be triggering that; will investigate that issue at some future time.
I was digging around myself with some trial and error, without much understanding, and the problem went away when I deleted this line from aomhilite.css:
Line 8: #aomhilite_size {max-width: 3em;}
Deleting the line seemed to have no effect on the little integer box itself, but the formatting of the entire page was much improved, that is, all the line widths were automatically wrapped according to the window width, instead of being fixed to some very small width.