Deleting group inside of group kick you out of the group.

Sorry, this is a bit convoluted. Ill number the groups for clarity, it requires three groups.

[group 2[group 1[group 0]]]

Selecting a group(1), that contains a group(0), and is also inside a group(2). Deleting the middle group group(1) kicks you out of the exterior group(2) even if there are other objects within the exterior group(2).