How can I detect if the user clicks into another window from my modal dialog

Use the Form.Deactivate event:

	this.Deactivate += new EventHandle(OnDeactivate);
	//...

	private void OnDeactivate(object s, EventArgs e) 
	{
    		this.Close();
	}

(from [email protected] on microsoft.public.dotnet.framework.windowsforms)