Merlin's Delphi Forge

The easiest and fastest way to find out if the Windows taskbar’s auto hide feature is on is to use the Windows SHAppBarMessage() function. Here’s the Object Pascal code port:

uses ShellAPI;
  ...
function TaskbarAutoHide: Boolean;
var
  ABData: TAppBarData;
begin
  ABData.cbSize := SizeOf(ABData);
  Result := ((SHAppBarMessage(ABM_GETSTATE, ABData) and ABS_AUTOHIDE) > 0);
end;