Sidebar preventing full width forums?

[semperaye]

Hello!

I am having trouble with my theme/sidebar/forum not sure exactly what one is to blame. Bbpress forums told me it’s not the forum and it’s my sidebar/theme. The forums look great when docked to the right of my 1920×1080 monitor, but when I maximize the screen the forums stay the same size as when docked. So basically the forums are not expanding to make up for the extra space when windows are maximized.

Example:
http://www.salamatphilippines.com/forums/forum/regions/luzon/cagayan-valley/

Thank you for taking the time to look into this for me, I am no expert. Is there some type of custom css that can fix this?

Thank you in advance!