The problem is maybe not a bug but rather a very irritating 
behaviour when trying to write cross-platform code. Some 
event types have changed between Delphi 1.0 and 2.0. 

For instance, the OnGetText events of TTable and TQuery haveĻ
changed their "var Text" parameter from "OpenString" to
"String" (meaning AnsiString, because VCL is compiled in
the $H+ state. 

This change causes all kinds of problems. I try to keep a singe
source code base for both the 32-bit and 16-bit versions of
my application. I tried to overcome the problem of the changed
parameter-type like this:

{$IFDEF VER90}
{$H+}
    procedure SQLQueryTimeGetText(Sender: TField; var Text: String;
      DisplayText: Boolean);
    procedure SQLQueryMMGetText(Sender: TField; var Text: String;
      DisplayText: Boolean);
{$H-}
{$ELSE}
    procedure SQLQueryTimeGetText(Sender: TField; var Text: OpenString;
      DisplayText: Boolean);
    procedure SQLQueryMMGetText(Sender: TField; var Text: OpenString;
      DisplayText: Boolean);
{$ENDIF}

This works fine at compile-time and the program runs as expected.
The irritation is that every time I save or recompile this unit,
Delphi runs some sort of source scanner on my code to verify 
that my event methods has the correct parameters. If the source
scanner had been as smart as the compiler, there would have been
no problem, but in Delphi 2.0 I now get the message:

"The SQLQueryTimeGetText method referenced by SQLQueryTime.OnGetText has
an incompatible parameter list. Remove the reference?"

for every such event I have a handler for. I have found no way to
avoid this message, even if my code is legal and correct. The
source scanner obviously searches the unit-file backwards and
do simple string comparisions. It knows nothing of IFDEFs or
type-declarations.

Worse, the default button on the message-box above is 'Yes' so if
I accidently press space or Enter, the reference to the event will
be gone. To correct this I tried to re-set the reference in the
field editor at design-time. But this operation uses the scanner
again and denies to set the event to my method. The only solution
to this is to physically move the 32-bit declaration in my unit
so that it comes last:

{$IFDEF VER80}
    procedure SQLQueryTimeGetText(Sender: TField; var Text: OpenString;
      DisplayText: Boolean);
    procedure SQLQueryMMGetText(Sender: TField; var Text: OpenString;
      DisplayText: Boolean);
{$ELSE}
{$H+}
    procedure SQLQueryTimeGetText(Sender: TField; var Text: String;
      DisplayText: Boolean);
    procedure SQLQueryMMGetText(Sender: TField; var Text: String;
      DisplayText: Boolean);
{$H-}
{$ENDIF}

Now things works as expected in Delphi 2.0, but then I have the same 
problem in Delphi 1.0.

I just realized that to avoid these messages I should simply remove
all design-time events and set my events at run-time in the FormCreate
method. This should work, but it is against Delphi-philosophy and is
probably not something that average Delphi users would think of.