Yellow background of Diacritic from Dead Key

[sil.linguist]

John,

is there a way to add yellow background to non-composing characters? (My terminology maybe off, forgive me.) Standard behavior on OSX 10.6+ is if you use a dead key plus a combining diacritic which will combine with another character to form a Unicode composite character, is when the dead key is hit then the diacritic will show with a yellow background... try it. with a U.S. QWERTY keyboard layout, command-e brings up _´_ [acute accent mark] before the key for the base character is stuck the background of the diacritic is yellow.  Now, I am using a unicode combining diacritic from which there are no composite characters. COMBINING MACRON BELOW U+0331 I have set this character up as a dead key but when I hit the dead key there is no yellow background. is there a way to force the yellow background?

[John Brownie]

I'm not sure myself, but I'll give you an answer off the top of my head.
I'm on holidays as I return to PNG from Australia, so I don't have the
time or internet access to do a lot of research.

My first guess is that you might only get the yellow background if you
have a terminator set. Perhaps you can set the terminator to be a space
plus the combining macron below.

Then again, it may end up being a case of non-Apple keyboards being
second-class citizens in the text input world.

Anyway, others might have a better idea.

John
--
John Brownie, john_b...@sil.org or j.br...@sil.org.pg
On furlough in Australia from:
Summer Institute of Linguistics | Mussau-Emira language, Mussau Is.
Ukarumpa, Eastern Highlands Province | New Ireland Province
Papua New Guinea | Papua New Guinea

[Geke]

Dear sil.linguist,

You seem to have the same problem as I have posted about on 30 June.
Here's a detailed description, first of how Apple's built-in keyboard layouts work, then how the layouts generated with Ukelele 2.2.1 behave. I write this mainly for John--maybe he gets an idea what's going on :-)

Normal behavior: After typing a dead key (in TextEdit) the terminator character is shown with a yellow background and the cursor blinking after it, as an indication that you are not in a standard situation but in the middle of typing an accented letter. After typing a second key (a key assigned a value in this dead key's state, the space bar, any other key) the yellow background goes away and the terminator character is replaced by one of three possibilities: 1. accented letter; 2. terminator; 3. terminator followed by second key's character.

Abnormal behavior: After typing the dead key, the terminator character is not shown: the cursor is blinking right after the previously typed character, just as if the dead key had not been typed. After typing a second key (the same three as above) the three possible results are: 1. accented letter; 2. terminator; 3. terminator.
In other words: as long as one doesn't type a non-assigned key after the dead key, the layout produces correct results, only the user interface behavior is awkward.

To narrow down the error, I opened the US layout packaged with Ukelele 2.2.1, gave it a different name and ID (900) and saved it as a keyboard layout (not as a bundle, that is) into my user's layouts folder. After activating it, this keyboard layout behaves exactly as described under "abnormal behavior" above. When I switch to the US layout that came built into the OS, the behavior is normal again.

I do all my work on Macs running 10.4.11, and when I tested my customized layout on a Mac running 10.6 it worked normally, so at first I thought the problem was limited to 10.4.11. But sil.linguist uses 10.6 and sees the same abnormal behavior, it seems.
My best guess now is that the error is related to keyboard layout ID conflicts, maybe combined with caches going awry, because the problem seems to appear only after a few custom keyboard layout installs, if I remember all my tests correctly.

Best regards,
Geke