OK -- this only seems to work when in full screen mode, which is also what causes that crash for me.Yes there is. I turn off the PP (post processing) via the pause key in game then alt tab to the tool.exe. After any changes I select save on the tool.exe Then back in the game use pause to turn the PP back on and you see the changes.
But as long as you change the settings before starting the game, it works fine using windowed mode without crash.