private void ObjectAnnotater_FormClosing(object sender, FormClosingEventArgs e) { if (btnSave.Enabled) //is modified { var result = MessageBox.Show("Do you want to save current changes ?", "Save annotations", MessageBoxButtons.YesNo, MessageBoxIcon.Information); if (result == System.Windows.Forms.DialogResult.Yes) { saveToFile(); } } drawingManager.Dispose(); }