451260 - Add ability to remove a content type in Tools > Options > Applications

Status: NEW

(Firefox :: Settings UI, enhancement)

Description

[skierpage]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1a2pre) Gecko/20080819034536 Minefield/3.1a2pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1a2pre) Gecko/20080819034536 Minefield/3.1a2pre

While playing around with FF 3.1's ogg handling, I created new application/ogg line in Tools > Options > Applications.  That didn't do what I wanted, so I wanted to remove it.  There's no way from the UI to do this.

Reproducible: Always

Steps to Reproduce:
Simple way: 
1.  Click Tools > Options > Advanced
2.  Try to delete one of those content types.

More realistic way:
1.  Go to some page that offers files with a mime type you've never encountered before.  In my case, http://www.djvu.org/docs/
2.  Click a file
3.  In the "Opening ...." dialog, choose Open with (I chose Notepad) and check "Do this automatically..."
4.  (File of the novel file type opens.)
5.  Now choose Tools > Options > Advanced.
6.  Try to delete the new content type.
Actual Results:  
You can't delete the content type association.

Expected Results:  
There has to be some way to remove a content type association.  If I click Application details in the drop down and click Remove, it goes back to "Always ask".  The UI could either be like about:config, where if you reset an option, it vanishes, or it could be explicit "Reset to default" which warns "This content type is not one of the defaults that came with Firefox, so if you reset to default it will be deleted (but you can set it up again later).

Presumably there's a workaround by editing a file somewhere.  The [Help] button didn't help.

Comment 2

[John Vandenberg]

Confirming on Linux.  bug 587988 is essentially the same for SeaMonkey.  I don't think this is a bug, because setting a content-type to 'Always ask' is essentially the same as removing it.  The only 'problem' is that mimetypes.rdf has an extra entry.

Comment 4

[rsx11m]

Bug 501163 implemented this for Thunderbird.

Comment 5

[Graham Perrin]

Attachment: Screen recording

As far as I can tell: 

- there's the option to remove
- removal is not persistent. 

Firefox 61.0 (64-bit) on FreeBSD-CURRENT, 

$ pkg info firefox | grep Version
Version        : 61.0_1,1
$ uname -v
FreeBSD 12.0-CURRENT #5 r335024: Wed Jun 13 11:04:24 BST 2018     root@momh167-gjp4-hpelitebook8570p-freebsd:/usr/obj/usr/src/amd64.amd64/sys/GENERIC

Comment 6

[Graham Perrin]

Attachment: The first of four frames from the screen recording.

Removing Tutanota …

Comment 7

[Graham Perrin]

Attachment: Second frame.

OK'ing the removal …

Comment 8

[Graham Perrin]

Attachment: Third frame.

Quitting, after preferring to use Thunderbird (default) …

Comment 9

[Graham Perrin]

Attachment: Fourth frame.

Tutanota, removed before quit, has reappeared. 

----

There's also the loss of preference to use Thunderbird, but that's a separate bug.