I went through the Preferences->Helper Applications procedure to add some new mime types, including application/gzip, and told it to always save to disk. But even after a restart, when I doubleclick on one of the .tar.gz files used for the mozilla build, I get a dialog saying that application/gzip is unrecognized by mozilla. The type did get added to my mimetypes.rdf, and it shows up in the Helper Apps pref pane, but the addition is being ignored.

not mine. over to mscott for evaluation

Changing summary. This is not just saving files: you can't add a new mime type with a helper app either (nothing I type in the dialog is saved), nor edit an existing mime type (the dialog comes up blank, and nothing I type in it is saved), nor specify a new helper app in the dialog that comes up when you go to a page with a new mime type (the "always use for this type" button is always greyed out). Basically, the helper app mechanism doesn't work at all, and I'm not sure why we even bother to offer the prefs pane. Increasing severity because it's starting to become a hassle that I can't view any PDF pages in 6.0. (I can probably figure out what file to edit and how, but Joe User won't be able to.)

One other thing: if you to to a page with PDF and get the "what application do you want to use?" dialog (which I shouldn't get in the first place, since prefs already tells me I have a helper app for application/pdf though it won't show me what the helper app is), I can't set focus or type in the text field in that dialog, so I can't even specify a one-time helper app there.

Looks like mozilla has made a mess of my mimeTypes.rdf. There are quite a few entries for pdf. I'll attach the current version of the file, then remove it and see if it regenerates something usable.

After I removed mimeTypes.rdf, I went to a page with pdf to get the dialog. Still couldn't type in the text field, but when I clicked the Browse button to get a file selection dialog, I was able to type in the fsb text field and select an application. "Always use this" was greyed out as usual, but was checked. It did correctly call up the acroread I chose, but did not remember that in my mime types as shown in prefs/helper apps.

Even after removing mimeTypes.rdf, I can't add the helper app in the prefs pane. When I click OK after filling out all the fields, I get: JavaScript error: line 0: uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIRDFContainer.Init]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: chrome://communicator/content/pref/overrideHandler.js :: anonymous :: line 242" data: no] If I click again, I get "a helper already exists for the type ..." but still nothing goes into the list shown in the prefs pane, and nothing gets written to mimeTypes.rdf.

akkana, we had a problem with profiles created before beta2 with corrupt mime types.rdf. Deleting the file didn't fix it either. I'd suggest either creating a new profile with the rtm version or creating a new profile and copying the clean mimetypes.rdf into your original profile directory. There was supposed to be a comment in the release notes about that (a minor note) but I never followed through to make sure it was fixed. There's nothing we can do to pre-emptively handle the corruption without user intervention. beta software..... =(