When viewing a PDF with spaces in the file name, such as "Week 1 day 2.pdf", Firefox attempts to load each space delimited portion in a separate tab. The file mentioned previously is thus separated so that the first tab is addressed to "file:///C:/Users/eugen/AppData/Local/Temp/Week", the second is addressed to "http://0.0.0.1/", what "1" automatically changes to when entered into the address bar, the third is addressed to http://www.day.com/, and the fourth to "http://www.2-2.pdf/". None of which load anything.