Well, just some thoughts:
a) I was thinking about this problem in the past, and my conclusion was to try to add a "UnboundDisplayFormat" property (if I recall correctly, I had problems naming it simply "displayformat"). I don't like adding properties in an already rich set (<g>), but that seemd to be the most powerful way. I do love controls that work unbound too.
b) have you enabled and tested the "AutoFill" property? It does the "auto-complete" part of your improvement

Final: you don't need any permission from the list, but is sometime very good, as you are doing, ask about impact and acceptance your planned changes can have. I did some improvements to that component, and it's incredible the different way it's used / locale date conventions / input standards. What was for me "the obvious fabolous improvement" (autofill), was a nightmare for some. So I had to introduce the autofill flag, and set it's default to False :)
You could also upload the changed source on the list "files" section for some test, but my changes were no tested I suspect, until introduced in the IBO standard release... and was too late.
But welcome in the IBO source improvements world. It's a fabolous set of components, and Jason is really open for improvements inclusion. You will sure love it.
regards
Marco Menardi
btw, one of the big "guru" for components here is Geoff Worboys, the author of the Enhanced set (http://www.telesiscomputing.com.au/enhcomp.htm)

--- In IBObjects@y..., "fabiobot" <fabiobot@y...> wrote:
> Hi,
>
> Using IB_DATE as an bound control i can change DisplayFormat
> property to something like "dd/mm/yyyy" to see the century (year
> with four digits).
>
> The problem is using IB_DATE as an unbound control, when i don't
> have DisplayFormat because it's a field property but i would like to
> see the year with four digits.
>
> With a small change this problem is corrected.
>
> I wrote a small change in IBC_DATE.IMP that will auto-complete the
> century if ShortDateFormat year is 'yyyy' (year with century).
> By example, if the user enter with:
>
> '08/19/' or '08/19/2' or '08/19/02' => will be changed
> to '08/19/2002' and the user will see this change.
>
> Always the current year is used in this conversion.
>
> I would like to obtain permission from the list
> to send this change to Jason Wharton.
> Somebody does not want this change?
>
> Thanks to all,
>
> Fabio R. Bot Silva.
> -------------------------------------
>
>
> The change is only in ValidateEdit procedure from IBC_DATE.IMP,
> see the code below (already is tested).
>
> {$IFDEF IBO_VCL40_OR_GREATER}
> procedure TIB_CustomDate.ValidateEdit;
> var
> tmpStr, S: string;
> I :Integer;
> begin
> tmpStr := FormatMaskText( EditMask, '' );
> if Text <> tmpStr then
> begin
> S := AnsiLowerCase(ShortDateFormat);
> if (Copy(S, Length(S) -3, 4) = 'yyyy') and
> (Length(Text) = Length(S)) then
> begin
> I := 4 - Length(Trim(Copy(Text, 7, 4)));
> if I > 0 then
> Text := Copy(Text, 1, 6) + Copy(DateToStr(Date), 7, I) +
> Copy(Text, 7, 4 - I);
> end;
>
> if not Assigned( Field ) then
> try
> StrToDate( Text );
> except
> if CanFocus then
> SetFocus;
> Raise;
> end;
> end;
>
> inherited ValidateEdit;
> end;
> {$ENDIF}