This feature is only available in Inspector Gadgets Pro.
Unity allows assets to be saved inside other assets to group them in the Project window, however it does not have an inbuilt way to add or remove those sub-assets manually so Inspector Gadgets gives you the ability to do so while holding
Alt (or you can set a different modifier key in the
This can be very useful for things like UI animations where you might have many Animation Clips which are only used in a single Animator Controller:
You can extract a sub-asset back into a regular asset by dropping it onto a folder. Unfortunately, it is not possible to just drop it into the blank area in the current folder.
Use a Version Control system like Git to backup your work before using this feature.
Unfortunately, some asset types cannot have sub-assets and some cannot be sub-assets, but Unity gives no warning if that is the case and will simply make the attempt, give an unhelpful error, and irreversibly corrupt the asset. So this tool validates the asset types and if a combination is unknown it will ask you to test it by using
Ctrl + D to Duplicate your assets before using it on your real assets.