Select the Variable part to enable your application to work with a part that is created at runtime. A variable is a place holder for the actual part, much like a parameter in an ordinary programming language.

You must place this part on the free-form surface outside the bounds of parts from the Canvas category, such as Window and Form parts.

When you add a variable to the free-form surface, you specify its class and connect the variable so that, at run time, it receives its identity from a part elsewhere in your application. At run time, a part of that class takes the place of the variable.

For example, you could add a variable to your application that contains Ordered Collection instances. At run time, with the appropriate connections, the ordered collection and its contents could be supplied from an external source such as a file.

To display the pop-up menu for the part, click with mouse button 2 on the part.

To further define the appearance and function of a part, double-click on it to open the properties window.