Strange bug in Aperture stacks visualisation
When in your project, if you want to see all the pics in a stack you can use the contextual menu (right click) then select "select all the pick from the stack", then type V to launch visualization: you have them all.
You can use shortcut cmd E instead of "select all the pick from the stack", it works.
However, if you have filtered your pics to show only top of stack, the first method works, but not the shortcut cmd E.
Mac Pro, Mac OS X (10.7.4), 2x2.66 dual core xeon