wsMaximized forms do not appear maximized

Question

Setting a form to WindowState = wsMaximized will sometimes cause the form to be maximized but not:

Long-time bug: this is a question I first asked in the Borland newsgroups in 2003:

• Accepted fix for WindowState = wsMaximized?

and then again in 2006:

• wsMaximized breaks it, NOT caused by Position=poScreenCenter, reproducible dfm

and then again in 2008:

• Forms not starting maximized

Someone asked it on the Embarcadero forums in 2012:

• Thread: Application not starting with maximized window

Now it's time to port the 18 year old bug to Stackoverflow. Maybe someone's finally figured out a workaround.

Steps to reproduce:

My posts contained half a dozen failure modes, but the easiest is:

• Drop a Label and an Edit on a form:

  

• Add an OnEnter event for the TEdit:

  procedure TForm1.Edit1Enter(Sender: TObject);
  begin
     Label1.Font.Style := Label1.Font.Style + [fsBold];
  end;
  

• and set the form:

  • WindowState to wsMaximized
  • AutoScroll to False

And bazinga, fails.

One of the other set of steps from the 2008 post:

1. Create a new app and a form.
2. Set the form to maximized (WindowState = wsMaximized) at design time.
3. Drop a ListView control on the form

4. During OnShow, add 20 empty items to the list view:

   procedure TForm1.FormShow(Sender: TObject);
   var
        i: Integer;
   begin
        for i := 1 to 20 do
             ListView1.Items.Add;
   
   end;
   

5. Set the form's AutoScroll property to false (AutoScroll = False) at design time

Of course what I'm not after is "fixed in version n of RadStudio. Just use that". I'm looking for an actual fix (if there is one); which could include quoting relevant changes to the VCL source when CodeGear finally did fix it. (If it is even fixed).

Note: Changing Position from poDesigned to anything else doesn't fix it.

Workaround

A horrible, ugly, awful, disgusting, workaround I had been using was to start a timer during OnShow, and then when the timer fires, maximize the form:

procedure TForm1.tmrVclMaximizeHackTimer(Sender: TObject);
begin
   Self.WindowState := wsMaximized;
end;

I later improved this hack to post a message during OnShow; which is essentially the same as a timer message, without having to use a timer:

const
  WM_MaximizeWindow = WM_APP + $03;

procedure TForm1.FormShow(Sender: TObject);
begin
  if (Self.WindowState = wsMaximized) then
  begin
     Self.WindowState := wsNormal;
     PostMessage(Self.Handle, WM_MaximizeWindow , 0, 0);
  end;
end;

private
   procedure WMMaximizeWindow(var Message: TMessage); message WM_MaximizeWindow;

procedure TForm1.WMMaximizeWindow(var Message: TMessage);
begin
   Self.WindowState := wsMaximized;
end;

Sometimes I invent the OnAfterShow event that Delphi never did:

const
  WM_AfterShow = WM_APP + $02;

procedure TForm1.FormShow(Sender: TObject);
begin
  PostMessage(Self.Handle, WM_AfterShow, 0, 0);
  if (Self.WindowState = wsMaximized) then
  begin
     Self.WindowState := wsNormal;
     FMaximizeNeeded := True;
  end;
end;

private
   procedure WMAfterShow(var Message: TMessage); message WM_AfterShow;

procedure TForm1.WMAfterShow(var Message: TMessage);
begin
   if FMaximizeNeeded then
   begin    
      FMaximizeNeeded := False;
      Self.WindowState := wsMaximized;
   end;
end;

But no hacks are better than hacks.

Answer 1

I Can reproduce with D7/Win7.

I don't use wsMaximized at all (similar random problems as you describe).

Workaround: