From Xojo Documentation
| This property has been deprecated since version 2008r5 and should no longer be used.
There is no replacement for this property.
Property (As Integer )
| This property is only available on the macOS platform.
For cross-platform development, use ＃If...＃Endif with the Target... specifiers to make sure you will not attempt to use this property on an incompatible platform.
The number of bytes in the file that makes up the resource fork.
Access to the resourcefork is supported only on Macintosh.