The remote is only capable of operating one device at a time (unless you have programmed advanced functions such as Volume, Channel or Transport control Punch-Through). When you press the Source Selector to operate your other product, such as the DVD player, the remote cannot control any other product, including the AVR, until you press the AVR Button again. To avoid your problem in the future, always press the AVR Button or appropriate Source Selector before you enter any command.