Ardour 2.8.7 - CTRL+Mouse Scroll Zoom IN/OUT does not work

Hi,
2.8.7 is faster and more stable than 2.8.5 (shutdown crash gone for me).
I set my desktop scroll to CMD+Mouse Scroll in order to free up CTRL+Mouse Scroll for Zoom IN/OUT unfortunately I am getting no response. ALT+ Mouse Scroll scrolls the timeline as expected.

Running Mac OS X 10.5.8 on a MacBook Pro.

mike