private void frm_settings_FormClosing(object sender, FormClosingEventArgs e)
{
// alert user of unsaved changes
if (btn_apply.Enabled)
{
var window = MessageBox.Show("You have unsaved changes, are you sure you want to close without saving ?",
"Unsaved Changes", MessageBoxButtons.YesNo);
if (window == DialogResult.No) e.Cancel = true;
else e.Cancel = false;
}
}