{
OnEnter, OnExit example (TWinControl)
This example uses an edit box and a memo control on a form. When either the edit box or the memo is the active control, it is colored yellow. When the active control becomes inactive, the color of the control returns to the Windows system color for a window.
} 
procedure TForm1.Edit1Enter(Sender: TObject);
begin
  Edit1.Color := clYellow;
end;
procedure TForm1.Edit1Exit(Sender: TObject);
begin
  Edit1.Color := clWindow;
end;
procedure TForm1.Memo1Enter(Sender: TObject);
begin
  Memo1.Color := clYellow;
end;
procedure TForm1.Memo1Exit(Sender: TObject);
begin
  Memo1.Color := clWindow;
end; 
