If the Navigator Preview is open in a file and you close that file and open another .pln file > what appears in the Navigator Preview in the second file is the image of the first file. The only way to see the current file's image in the Navigator Preview is to Quit ArchiCAD and reopen the file.
I haven't experienced this, but quitting AC seems rather drastic. Have you tried doube clicking in the Preview window or accessing Refdraw Preview from it's flyout?
