found this in the default_quickbars.ini
Code:
QUICKBAR 0 0
0 0 0 command hail
0 0 1 command attack
0 0 2 command sit
0 0 3 command yell
0 0 9 command bug
1 0 0 macro Take a Screenshot:cl_screenshot 1
1 0 1 macro Shadows On/Off:ui $r_shadows = !r_shadows
1 0 2 macro Water:ui $r_updateplanarreflectionmaps = !$r_updateplanarreflectionmaps
so maybe if you put in the 'OnPress=$show_window mainhud.statbar = !hide_window statbar'