I noticed this a while ago, but didnt post anything about it.
This scared me for a second because I needed something like this for something I'm making, but then I remembered the [scratchblocks]([costume # v] of [ v])[/scratchblocks] exists.
Stick it under a what I start as a clone block
Oh, well I thought it worked like the UI for sprites
So first of all, INHERIT doesn't do anything for sprites that aren't clones. For clones, that menu is populated with all the things this clone could inherit from its parent (sprite-local variables and blocks, certain attributes) but isn't already inheriting. Read the sprite OOP chapter in the manual.