Unexpected user key/entry behavior (data loss) (8151)

[TravisE]

I have a physical HP Prime with firmware version 8151 and just experienced something ugly while entering a program. I have a program 'USERKEYS' with the following:

Code:


KEY KSA_Space()
BEGIN
RETURN " ";
END

KEY KA_Dot()
BEGIN
RETURN ":=";
END;

KEY KSA_Dot()
BEGIN
RETURN ":=";
END

I had user key mode locked on and was editing a program. I held down both Shift and Alpha while typing alphabetic keys (to quickly enter lowercase) and while holding them, happened to press the Space key. Instead of entering a space like usual, the cursor inexplicably jumped to a random location, and a large chunk of code instantly vanished with no warning or explanation.

I find I can reproduce this in the editor or Home entry line as long as there is enough text (say, at least a few dozen characters or so), though it doesn't seem to happen if the current entry is very short. It happens when I activate either 1-user or user-lock and make the next “key” be a simultaneous Shift-Alpha-Space press (as in, pressing all three keys at once).

I don't understand why this is happening, but it's pretty dangerous. Fortunately I was able to force an On+Symb reboot to retrieve an earlier editing session with most of my lost code intact.