Don't forget "Border" checkbox in render settings when clicking CTRL + ALT + B

I often wanna have my render preview to render only the view of camera and then ignore everything else. (render settings, border checkbox) That's because it renders my preview lot faster since the rendering area is smaller. Ok, but sometimes I want to have it even faster and I use CTRL + B (border select tool) to select some specific area from my project to change it's materials faster. I've noted that Blender crashes more often if I change the material of some object that is in scene and which nodes I'm changing and if I have really huge area that I'm changing. That's why I select as small area as possible always to make my workflow fluent and make less Blender crashes.

But the problem is that I can't now go back to the original camera render mode, cause clicking CTRL + ALT + B removes that checkbox from my project instead what I actually wanted to do: go back to the original setting before CTRL + B. If I have clicked it on, I wish it would stay on until I click it off by myself.

This is exactly what I wish would happen If i had the border checkbox selected: dl.dropboxusercontent.com/u/5904620/Blender_aid/border%20select.gif