File -> Open File produces an os panel in which the majority of files of interest, i.e. .html, .jpg, .gif, .pdf, are greyed out (unselectable) and so cannot be opened in the web browser. Directories are traversable and files of type .txt are selectable and do open and display correctly. These un-selectable files can be opened in the browser window by typing the full path into the navigation panel thus: file///blah/blat/splat.gif displays the content that cannot be selected using the File -> Open File drop-down menu. So I know it's not a permission problem.