Dropping a component in a gap inserts it at the start/end of its parent

[mhsmith]

In a gap between siblings, the mouse pointer is over the parent element, so the actual insertion point will be either the start or the end of the parent, whichever is closer. If you want to insert something into a gap, you have to drop it NOT on the gap, but on one of the adjacent siblings.

This obviously isn't intuitive, and the larger the gap is, the worse it gets.