keydown problem

I have a textfield that is supposed to accept only bengali characters. To this end, in the keydown event of the textfield I have this code:
if instr(kBanglaChars, key) > 0 then//kBanglaChar is constant containing all the bengali characters and punctuations.
return false
end if
return true

Now, all the characters pass thru except character &u09CD (the special chr allowing to merge two glyphs into one single glyph).
I tried also: if key = &u09CD then…, but it doesnt work.
By the way, disabling the keydown event, the character works OK.
Any idea how to solve the problem?
Thanks, Carlo

[quote=201367:@Carlo Rubini]I have a textfield that is supposed to accept only bengali characters. To this end, in the keydown event of the textfield I have this code:
if instr(kBanglaChars, key) > 0 then//kBanglaChar is constant containing all the bengali characters and punctuations.
return false
end if
return true

Now, all the characters pass thru except character &u09CD (the special chr allowing to merge two glyphs into one single glyph).
I tried also: if key = &u09CD then…, but it doesnt work.
By the way, disabling the keydown event, the character works OK.
Any idea how to solve the problem?
Thanks, Carlo[/quote]

Non advancing characters may not necessarily appear in your constant. For instance on Mac if I punch ^i on a French keyboard I obtain î. But in Keydown, I get chr(0) and chr(105) (which is î). Never the non advancing ^. Same thing for ¨or `.

Fine, adding chr(0) solved the problem.
Thanks.