Game keeps adding new fuel tank tab thingy when I press the X button to delete it

[delicate spoke]

https://forum.kerbalspaceprogram.com/topic/221354-resource-manager-rm-disallows-re-placement-of-a-resource-in-the-transfer-list-of-the-rm-creating-duplicates-in-the-parts-list-of-the-rm/#comment-4348800