This problem is caused by a long-standing bug in Firefox that only allows the first page (or first few pages) of some web pages to be previewed or printed. If you disable Print Edit WE and then use ‘File > Print Preview’, you will see that the problem happens without Print Edit WE.

However, you can use the ‘Fix Page Breaks’ command (on the 'Tools' button menu) in Print Edit WE to work around this Firefox bug on many web pages.