Can't Delete items

Ok, a little spoiler alert for people actualy interested in this.

So I just did a quest where my potential rewards were either a one day only flying jet squirel (the vehicle not an actual squirel) or better fuel for my curret vehicle.

Now I chose the fuel [Liquid Fuel S3] which gives me a 75% speed boost while I'm on the vehicle so I thought I would delete my old fuel [EV Liquid Fuel S2] (which gave me only 38% speed boost) but I seem to be unable to do that.

I just click "ok" on the delete button from my inventory but it never leaves my inventory.

I'm the sort of guy who forgets to empty his inventory until an annotation tells me that it's full so an extra inventory slot would be really useful.

Quote from Ultranovaxstyle

If you put your mouse on liquid fuel,on the bottom you will see that it write Binds and/or no-sale so you cant delete it,but still you can just throw it out of your inventory by dragging them anywhere except your inventory and press left click

That's how I was trying to delete it, but it doesn't seem to work.

Also I was under the impression that "Bind" meant non tradebale/sellable. I've never seen something been undeletable.

I mean, I guess it's a way to foolproof the game especially for an item tha you get so early on, bur come on.