Thank-you for the reply -- I already understood the work-around... my question was really "why?" .
I'm not sure I get why polygons and circles will allow direct editing and other shapes do not -- they are all built of the same stuff and the specialized edibility of the shapes (eg- up/down arrow, etc.) does not persist so why the counter-intuitive difference in the way some shapes are handled? (which BTW is not documented, which is why I thought it might be a bug)
The one that puzzles me the most is the ellipse... the others I can see there is some sort of recalculation of the rounded corners taking place during scale operations (or something).
The reason I ask is I have to explain it to others and "just because" isn't an answer I like to give.
Also, it might be a feature request to have some sort of explode context click command for these special shapes as the split thing is less than ideal -- you end up with extra points that aren't easy to get rid of or heal... best case scenario it takes 6 clicks to get to an clean editable state.
Best,
Jason.