This one's been around for awhile. Run a user application that binds to the display and some buttons, then put the player into standby (hold down the top button.) When the player comes back from standby, the app is no longer in the foreground. Holding down the knob to bring up the Hijack menu instead brings up an image of the app in question, but when you scroll the knob, the Hijack menu flashes. There's no way to get the app back to a "normal" state short of a reboot (that I've found.)

I had been working around this in emphatic by catching when the player goes into standby in the flash savearea, and calling WAITMENU to re-bind to the Hijack menu. The user had to select the app from the Hijack menu upon waking up. This was an okay workaround, but not ideal. Furthermore, for some reason, when the player goes into standby in the car (as a result of the key being turned off) this workaround doesn't work for some reason that I haven't figured out yet.

Anyway, the ideal thing would be for whatever app was in the foreground to regain control of the display and input once the player wakes up from standby. Hope it's doable.