AkelPad

When deleting back midst of Korean IME input(not completing), Akelpad edit control leaves one '' instead of clearing. (HEX 1B)

silversoul
Can you make demontration with screenshots or video?

Before input


Typing Korean consonant 'ㄱ', IME entered, IME waits for continuing vowel input:


Typing backspace, cancelling before full letter construction:




When after 'ㄱ', Korean vowel 'ㅏ' and consonant 'ㄴ' have been typed, IME considers '가' is completed and continue waiting with 'ㄴ':


And backspace:


And backspace:


And again. Completed letter (가) does not make residue.:

silversoul
If I understand correctly: since letter '가' is completed its erased with backspace. Or if not: can you write what result do you expect?

While building letter, each Vowels(cf.'ㄱ') and Consontants(cf.'ㅏ') are deleted by every BKSP hit. When IME completes its construction of letter(complex)(cf.'가'), it is regarded as one character block and deleted letter by letter.

Therefore, it should be like this:
'ㄱ' -> 'ㄱ' (currently: 'ㄱ')
'ㄱ' + BKSP -> '' (currently : arrow character)
'ㄱ' + 'ㅏ' -> '가' (currently : '가')
'ㄱ' + 'ㅏ' + BKSP -> 'ㄱ' (currently : 'ㄱ')
'ㄱ' + 'ㅏ' + BKSP + BKSP -> '' (currently : arrow character)

I don't know why, but I found wParam of AE_EditProc handles 0x1b when lParam=GCS_COMPSTR & BKSP deletes to letter 'none'.
Surely, the message sent is WM_IME_COMPOSITION.