VCL Delphi

Question:
How can I make a form move by clicking and dragging in the
client area instead of on the caption bar?
Answer:
You could trap the mouse move messages, and move the form
based on the net movement of the mouse. An easy way to
achieve the same result is to make Windows believe the
caption bar was clicked on by trapping and modifying the
WM_NCHITTEST message.
Example:
type
TForm1 = class(TForm)
private
{ Private declarations }
public
procedure WMNCHitTest(var M: TWMNCHitTest);
message WM_NCHITTEST;
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.WMNCHitTest(var M: TWMNCHitTest);
begin
inherited;
{If the client has been clicked, make Windows believe}
{it was the caption bar that was clicked on}
if M.Result = htClient then
M.Result := htCaption;
end;