Macros

i had that too for a while and 'fixed' it to do it this way:
F5:[previous message]
↓
F5:[previo]
↓
F5:[pnew message]
↓
F5:[new message]

You just need too see youre sentence isn't marked, than just hold 1 letter of te prev. message and type youre new one, than delete that one letter.