FolderItem.ExtensionVisible Property
Syntax
ExtensionVisible as Boolean
Allows you to tell whether a given file has its file extension hidden or visible, or toggle that status. Note that when you change this setting, the operating system's Desktop Manager or subsequent Navigation dialogs may not reflect the change right away.
When you create a new file under Mac OS X, REALbasic sets the "hide extension" flag according to the current value of this property. On Windows, hiding the file extension is a global property, so if it is true for one FolderItem on the user's computer it is true for all of them.