My understanding (completely self-generated, but based on some knowledge of basic computer programming) is that the routine that handles the input is looking for four digits and if it doesn't get them it's not going to work.

Which seems wrong to me. The fact that you are holding down a modifier key (the Alt key in this case) should be all that is necessary. Leading zeros add nothing to the mix. 70, 070, 0070 are all 70.

Of course, tsuwm's point is well-taken. 0177 does look a lot like octal. In my original posting to the thread about the Unicode value, I prepended a 0x to the number indicating it was hexadecimal.

Ceci n'est pas un seing.