The file format for WS7 has not changed from WS6 but, since WS7 had not been published when XtreeGold 2.5 was being written, this version of XTree is unable to format WS7 files. To get a formatted view of a WS7 file, XTree has to be fooled into thinking the file was produced by WS6. Fortunately this is simple to do, and it can all be done within XTree's View function.
First of all check in Configuration (Alt-F10) under Security that modifications to files in hex view mode are allowed. Then select the WS7 file and hit V to view it. Then hit H to change to Hex mode and E to Edit. Cursor right 8 times to the fifth byte, which is 70 indicating that the file was created by WordStar 7.0. Key 6 to change the byte from 70 to 60. Then hit Return and Y to save the modification to disk. If you now hit F you will have a properly formatted view of your document.
XTree Gold 3.0 has a WordStar 7 viewer, so this tip is unnecessary.
Tom Ruben