Maintain nesting level. Prevent item being dropped in parent but allow another container of same level

[LrntL]

Hi !

I use connected list.
I use two times nestedSortable :

• The 1st to manage category and subcategory on 2 levels (not connected)
• The 2nd to manage item (in these categories/subcategories), connected with css class on 1 level.

What I want is to drag item from a category/subcategory to another without be able to drop it in the root of the categories.

Dropping item in another category/subcategory is working but I can't prevent dropping in root of the categories.

Do you know how to do that ?

For you interest, take a look at this fork (in development) : https://github.com/CanopyApps/nestedSortable/tree/develop

It has "maintainNestingLevel" option when set to true does what I need.
I do not know how to apply that in this plugin.