Foxit Reader Provides two ways for you to open PDFs in multiple Foxit PDF Reader Windows. Following is an introduction to these two methods.
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.
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.
Note: This tear a tab out method is available in Foxit PDF Reader 9.4 and higher versions.