Non-empty GroupItem is invisible in 2D View

Group and it's children is visible during Live Preview and application run.

Green circle in 2D View represents the place where one of the GroupItems children should be.
Green circles in States View represents the successfully rendered rectangles on a state preview.
Green box in Code View is the code for GroupItem itself.
GroupItem disappears in Navigator hierarchy if I flick "show only visible components", even if it has children.