Hi axel.dian,

• Click on menu icon.
• Click on options.
• In left pane you will see General options, Click on it.
• In this menu, you will find Applications options.
• Choose Open in Firefox For Portable Document Format(PDF) as shown in screenshot.

Hope it helps. Thank You.

Hello..

For now, I suppose the workaround is to open the FDF externally (i.e., in Reader or Acrobat and not the plugin).

You can search for known bugs relating to FDFs, or file a new report, in Bugzilla .

Make sure you have selected "Preview in Firefox" "Open in Firefox" for Portable Document Format (PDF) files to use the builtin PDF Viewer and not merely the Firefox application.

• Options/Preferences -> General -> Applications
• https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file

You get tabs opening endlessly if you select Firefox as the application to handle a file when you get an "Open with" dialog.

• https://support.mozilla.org/en-US/kb/firefox-repeatedly-opens-empty-tabs-or-windows

See also:

• https://support.mozilla.org/en-US/kb/view-pdf-files-firefox
• https://support.mozilla.org/en-US/kb/disable-built-pdf-viewer-and-use-another-viewer

For now, I suppose the workaround is to open the FDF externally (i.e., in Reader or Acrobat and not the plugin).

You can search for known bugs relating to FDFs, or file a new report, in Bugzilla.

Thank you so much cor-el and Shashank Shekhar, you solved my problem !