How to upgrade only ONE stash tab to merchant tab?

Hi GGG team,

Please fix this.
In www UI I have only option that looks like will swap all my current premium tabs to merchant which I do not want.

Have only one button there which will show this:
"Are you sure you want to upgrade this Upgrade to Premium Stash Tab and Extra Stash Tab to a Merchant's Tab?"

And even if I will get option after this based on description I will not confirm something that is against something that I want so either way its described improperly.

Thanks in advance.