From Xojo Documentation
These are the controls and classes in the Controllers group of the Library.
The controls in this section are all non-visual. They do not display on the Web Page in the built app and the user cannot see or interact with them. When added to a Layout, they appear on the Shelf area.
Adding these controls to the Layout is merely a convenience to give you easy access to their event handlers. Although you can also create these controls in using the New operator you will not have access to the event handlers unless you first subclass the control (and access the event handlers there) or use the AddHandler command to map event handlers to methods on the web page.
You can also add just about any non-visual class to a layout by dragging the Object control onto the layout and changing its Super to the class you want.
Provides a quick way to run Unix or DOS shell commands.
Although the SerialConnection control displays an icon when placed in a window in the Window Editor, it is not visible in the built application. It is designed only for executing code to communicate via the serial port. For more information, refer to the UserGuide:Serial Devices topic.
Use this generic object to add any class to the layout so it can work as a non-visual control, giving you easy access to all its event handlers. Drag the Object to the layout and then change its Super property to your actual class name.
The XojoScript control allows the end user to write and execute Xojo code within a compiled app. Scripts are compiled into machine code.
You pass the code that you want to run via the Source property and execute it by issuing the Run method.