Strange behavior while parent inside a group

[alex.motion]

Hello ! 

looks like parenting is not working properly inside a group , is that a bug or it should be like that ? 

it behaves strange. 

Create 3 teapots , group them , open group ,parent teapot 1 with teapot 2 by dragging one it over another 

dragging refuses to work inside group, but with select and link it works  but group container becomes smaller than it should be.