How to stop the Trees in the Categories View Workspace from auto-expanding

[Damit]

I was playing with the Categories View workspace dragging all externally generated keywords into a @keywords Parent category I am temporarily calling [] Outsourced.  Whenever I drag or past another @ keyword category into [] Outsourced, it expands.  Is there a way to stop this behavior?

[Mario]

This behavior is by design. It has to expand child items so you can drop files on them. It cannot know what your actual drop target is.

Alternatively consider using the Categories Panel.
Select all the files for a keyword, then check the corresponding @keyword in the Categories panel.

This panel has a button in the toolbar that creates a new category from a name you type in and assigns all selected files to it. I would think that this is a more efficient workflow than drag & drop in this case. See Creating a Category from All Selected Files