How to add more controls?
Using CONTROLL ADD ClassName ... functionality will allow the creation of almost any Windows controls.
A control is a child window an application uses in conjunction with another window to perform simple input and output (I/O) tasks. Controls are most often used within dialog boxes, but they can also be used in other windows. Controls within dialog boxes provide the user with the means to type text, choose options, and direct a dialog box to complete its action. Controls in other windows provide a variety of services, such as letting the user choose commands, view status, and view and edit text. The user control overviews discuss how to use these controls.
What is a classname?
ClassName may be a string expression, quoted string literal, or a string equate.
More info on Windows controls and relative class names can be found at http://msdn.microsoft.com/en-us/library/bb773169(VS.85).aspx
Are there any other controls?
thinBasic has also developed some home made controls. See topics below this one for the list.