I noticed in include/Core/System/Chars.h that there is a vchrAutoOff virtual key code. I am new to the PalmOS, but I imagine that a keyDownEvent pops out of EvtGetEvent before an auto-shutoff with this KeyDown.chr. There is also a vchrPowerOff virtual key code which more generally signals both hard-key and auto power-off occurances, but this is only in PalmOS 3.2 and later.
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