Firefox will always open a local text file in a browser tab. A MIME type only applies to files from a (local) web server and not for files that you open locally via file://

See:

• http://kb.mozillazine.org/view_source.editor.external
• http://kb.mozillazine.org/view_source.editor.path

External Application Buttons mod for Firefox 3.0+: https://addons.mozilla.org/firefox/addon/12892

Since Firefox didn't seem to make any difference between local files and server files (as opposed to MSIE, which does) I saw the only chance to alter the unwanted behavior in changing the MIME type handling – but however, this didn't succeed even for server files, since the handling of internal MIME types like text/plain apparently can't be changed anyway ... which we do not have to understand :|

I already edited the values view_source.editor.external and view_source.editor.path ... unfortunately this only has effect on viewing source code (e.g. by Ctrl+U), but not on the loading of txt-files; neither locally (file:///) nor remote (http://).

If this could be influenced in the same way as source code viewing, that would be the solution.

Once the file has opened in a tab you can use "View > Page Source" to open the file in the text editor. I don't know of a way to override the default behavior for files send as text/plain, so you will have to do that extra step.

A possibility is to create a custom button that prompts for a link and opens that link in that text editor.

The first suggestion of course is self-evident, and therefore pressing Ctrl+U (see my last posting where this was mentioned already) after opening a text file has been my workaround ever since.

The second suggestion (basically producing the same effect) for me is not an expedient alternative since I mostly use the keyboard – and have to use it anyway once the editor has opened up.

The disadvantage of both is that an external editor doesn't provide clickable links as the internal source code viewer does (which is why I would like to keep the latter) and that these are only workarounds not solving the original problem.

Having reached this point already, I posted my request above ... ;)

I don't know if this will help with the original inquiry or not, but I may have found an extremely limited solution with the LocalLink extension: https://addons.mozilla.org/en-US/firefox/addon/locallink/

Once this add-on is installed, the following file formats can be opened in their own applications from FireFox bookmarks: -- .doc -- .rft

These files all open in and download (as a new file) from the browser: -- .pdf -- .xls -- .exe

The following files all open (and display) in the browser and are not editable: -- .jpg -- .gif -- .txt

In light of all these limitations, I'm wondering: has anyone else found a better solution to opening local files from the Bookmarks manager?

Dear Metta,

thanks for replying to the subject, and sorry for my late answer.

Unfortunately, this add-on deals with a completely different matter. Regarding the description on the extension homepage it affects the handling of file://-links on webpages with http://-links only.

Bookmarks of .doc, .rtf, .xls and other office file formats open these documents as downloads (not being displayed in the browser) anyway, this is the default behavior. Once you have checked the option "Do this automatically for files like this from now on" all the according documents are opened in their own applications directly without seeing the firefox open dialog.

So if you encounter different behavoir concerning these file formats this is only dependent on you personal settings, but not on the add-on you have mentioned.

Apart from that, this wouldn't solve the original problem, since this is only related to the handling of internal MIME types (like text/plain = .txt format) as specified in my first post, but not to file types that are external anyway.