Sales/Purchases: Prompt to save changes after changing sales/purchase type

It would also be extremely helpful to have a 'warning' appear in 'Enter sales' window for example: should someone be entering a quote and then if they go to change the sales layout type to invoice, without first saving it - a warning prompting them to 'save/record' their data first  would stop someone from loosing the data they've typed and most importantly the item prices that were originally entered.  Without a warning, an invoice can accidently be sent to a client with incorrect prices or the person entering the data has to do it all over again!

"Warning prompt in Enter Sales window if change sales type without first saving data"