WP34s alpha confusion

[c785]

Hi,

I'm puzzled about alpha mode. I just took a blank (erased) WP34s emulator in and reproduced the same weird behaviour as on the real device:

1. Pick TVM from Lib and copy it to RAM.
2. Enter programming mode.
3. Scroll to step 6, "alpha'ver'".
4. Here we try to insert one more alpha by pressing f-ENTER. Now "INPUT" lights up, but no new step gets entered.
5a. We want to append "ABC" to alpha, so we press A, which now creates a new step "alpha A". Not quite what I expect.
5b. Instead, we press ENTER (just like in LBL entry), but that just cancels alpha mode.
5c. Strangely, even when we scroll up and down with the arrow keys instead of entering anything, INPUT remains active.

For the alternatives 5a/b/c, it is best to delete the program from RAM and start over from step 1.

What am I missing here? I expect f-ENTER to allow me to enter three characters, not this.