When I open a file it wont stop opening the same window?
When a PDF file opens in a new tab it keeps opening tabs and will not stop or load the file.
When a PDF file opens in a new tab it keeps opening tabs and will not stop or load the file.
Alla svar (1)
More than likely that is an issue with what you have selected to open PDF files.
Please see these support articles: https://support.mozilla.org/en-US/kb/firefox-repeatedly-opens-empty-tabs-or-windows
https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file