Using latest nightly: 7th. October, 2012, Linux.
I select the bar where I change vid_conheight in the menus.
I can either use "backspace" or "enter" .. it always decreases the conheight.
"backspace" is correct. But "enter" is supposed to increase the vid_conheight value.
Can't reproduce that one. Which menu and option are you using? It seems like its called "Font" and for me enter increases and backspace decreases size.
Closing - confirmed as working in 3.1