Request Delete button in Convert Dialogs

I know we can "Shift + Delete" on removing old/unused convert strings in drop-down box but how about a button to automate that with confirmation?

Perhaps not a button but still a function to delete an entry: see the right-arrow-button next to the input box. In the menu you will find a function to delete a single entry or all of them (look at the bottom of the menu).

Lol. I've never used that button. I don't know why. Thanks again.