#4 avoid having to press 'save changes'

[Andrew Chapman]

When working in the render pass manager, it would be
good if it applied the changes as you made them rather
than having to click 'save changes' all the time. I'm
sure people are missing that from time to time and
losing their changes.

Or at least it should warn when there are unsaved
changes before closing the window or displaying a
different pass or override.