I notice that when I reduce the width of a window which has CommandBars, to the point where some command bars become semi-hidden (with "More" arrows), the bars on the left are the first to become semi-hidden, while the ones on the right remain fully visible.
This seems the wrong way round to me, as the leftmost bar is generally the most important.
MS Office, which I believe the action framework is based on, hides the rightmost bar first.