Изменить экранный курсор без необходимости возвращать предыдущий

// By implementing Interface we can set the cursor without restore it in the end. 
// Example: In convensional way... 
var
  Cur: TCursor;
begin
  Cur := Screen.Cursor;
  Screen.Cursor := crSQLWait;
  //do coding here 
 //What happend is that if your code did not finish, the screen cursor will 
 //remain as crSQLWait.. even with try..finally block (sometimes) 
 Screen.Cursor := Cur;
end;

// By using interface, we can implement as follows 
type
  ImyCursor = interface
    [(GUID - Ctrl - Shift - G)]
  end;
  TmyCursor = class(TInterfacedObjects, ImyCursor);
  private
    FCursor: TCursor;
  public
    constructor Create;
    destructor Destroy; override;
  end;

implementation

TmyCursor.Create;

begin
  FCursor := Screen.Cursor;
end;

TmyCursor.Destroy;

begin
  Screen.Cursor := FCursor;
  inherited;
end;

procedure....
var
  C: ImyCursor;
begin
  C := TmyCursor.Create;
  Screen.Curosr := crSQLWait; // whatever cursor you like 
  // Do coding here without worring to free it. 
  // Screen Cursor will restore when the TMyCursor object get out of scope. 
end;