MacBook Email recently started changing the order of mailboxes in side menu

I have kept my mailbox order the same way for years, but recently, my MacBook has decided to randomly change the order they are displayed in most frequently placing my least used mailbox at the top of the list. I do not understand why these very irritating things randomly occur, but I simply want to set the order of my mailboxes to that of my choosing without them being changed or altered in any way. For example, my "sent" mailbox keeps moving itself to the top of my list. I want it to stay at the bottom where I move it every day. Why are they rearranging themselves, and how do I get it to stop?

I have attached a screenshot for clarification in case I am not using the proper terminology.