Tab sequence with drop down list: Is there a way to define a tab sequence that inlcudes my own drop down list?
Yes, use the screen coordinates specified in the DropDownList command. Example:

DropDownList (12,59) "Notification type" refer="V[ntype]" width=25

Tab  F[Notification date]  #[12,59]
Tab   #[12,59]   F[Cost center]