This package improves inspector arrays automatically, no need for any code changes. Simply install and enjoy reorderable arrays in your inspector.

If you use custom inspectors, you could simple extend the ReorderableArrayEditor instead of Editor.

If you have an array property which you wouldn't like to be reorderable, you could simply give it the attribute [NotReorderable].

Features:

+ drag 'n' drop support: simply drag one or more resources onto the header of the reorderable array to add all items.

+ reorder items: simply grab the left handle and drag it up or down.

+ foldable: the arrays are foldable as always

+ nested arrays: enable nested reorderable arrays via menu

Enjoy!