You work as a Windows Application Developer for ABC Inc.

You work as a Windows Application Developer for ABC Inc. The company uses Visual Studio .NET as its application development platform. You create a Windows application using .NET Framework 2.0. The application allows computer engineers to design circuit boards for different types of hardware. You create a custom control that represents the design surface. You are required to highlight the vacant areas on the design surface where a component can be dropped. Which of the following events will you use to accomplish this task?