Follow these guidelines for copy, move, and deletion operations in the ELH hierarchy.

If you delete a node, its subordinates are deleted. If you do not delete the subordinates first, a message is displayed to warn you that if you click OK, the subordinates will be deleted.

You cannot move two or more symbols if any of them are hierarchy symbols, unless the ones you're moving will form a complete hierarchy on their own. To move a hierarchy, select the top symbol only; all the subordinates come along.

You can copy any collection of hierarchy and non-hierarchy symbols onto the Clipboard, but there are restrictions on how they're pasted back onto an ELH diagram:

If the material in the Clipboard is a single hierarchy, you can append it anywhere on an existing hierarchy on the target diagram.

If the material is more than one hierarchy, or it is non-hierarchical, you can only paste it onto the target diagram separate from a hierarchy.

You cannot move objects that would place a sub-hierarchy within itself.

You cannot have more than 24 levels in a hierarchy.