Hide Windows TaskBar

Windows' taskbar is just a window, like any other window. You can hide or show it with the function ShowWindow, given its handle. And you can get the handle of the taskbar with the function FindWindow.

By cleverly combining these two functions, you can hide Windows' taskbar from within your Delphi program with only 1 line of code:

procedure TForm1.Button1Click((Sender: TObject);
begin
  ShowWindow(FindWindow('Shell_TrayWnd', nil), SW_HIDE);
end;

To show the taskbar again, use ShowWindow with another parameter:

procedure TForm1.SetEditsColor(NewColor: TColor);
begin
  ShowWindow(FindWindow('Shell_TrayWnd', nil), SW_SHOW);
end;

Related articles:

Hide application from Taskbar
How to hide a program's "button" from the TaskBar.