How to open PDFs in multiple Foxit PDF Reader Windows

Make Allow Multiple Instances option checked in Preferences

Please go to File tab in Foxit PDF Reader> Preferences > Documents > Open Setting > check Allow Multiple Instances, click on OK button to enable single document interface mode in Foxit PDF Reader. This setting will enable Foxit PDF Reader to create a new separate window when double-click to open a PDF file.

Tear a tab out to become a new window

When you open some PDF files in multiple tabs in a single Foxit PDF Reader window, please drag and drop a file tab outside of the existing window to create a new instance and view the PDF file in that individual window.