To add WinAmp's solid dragging behaviour to a form, use the following
variable declaration and methods.  Note that with this code, any part of
the form not otherwise populated with buttons etc can be used to drag
the form.  If you wanted to have a special form area for dragging - i.e.
the equivalent of a title-bar - you would just make the FormMouseDown
method a little more complex by adding a check whether X and Y were
within certain bounds.

var IsDragging : boolean;
    OriginalX, OriginalY : integer;

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var DeltaX,DeltaY : integer;
begin
   if IsDragging then
      begin
         DeltaX:=X-OriginalX;
         DeltaY:=Y-OriginalY;
         Left:=Left+DeltaX;
         Top:=Top+DeltaY
      end;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
   IsDragging:=true;
   OriginalX:=X;
   OriginalY:=Y;
end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
   IsDragging:=False;
end;

Works in D1 and I am sure later versions too.

--
David Gosnell
These personal views are not necessarily those of my employer.
(please remove "uce-buster." from my e-mail address if replying direct)

Take a look at my TFormShaper.
Additionally to the capability to create nonrectangular TForms it
provides a property WindowMove.
You can select one of this options to move the TForm
TYPE TMoveOption = (NoMove,FullMove,SystemMove);
FullMove    -> traps WM_LButtonDown,WM_LButtonUp and WM_MouseMove
SystemMove  -> traps WM_NcHitTest

Andreas Heckel
http://www.wirtschaft.tu-ilmenau.de/~aeg