Grouped objects - Adding/Removing objects to a group

A good trick for adding to a group, without loosing existing effects, like animations, for the existing group, is to: 1) select a shape that is already a member of the group, 2) ctrl-drag the existing shape to create a copy of the shape  - this will be a member of the existing group, 3) use the "change shape" feature to change the type of the new shape to whatever shape you need, 4) finish editing your new shape to have the characteristics you want.    I have not used this a lot yet, but I have used it, and it works for me.  Note that copying and pasting an existing object does not seem to make the new shape be a member of the group, only ctrl-drag copying.   I've only tried this in PPT 2010.