Many people use Firefox as the browser of choice.  I myself make use of it for the excellent FireBug add-in.  If you do use Firefox against your SharePoint sites you will have see the, how would you say, different experience when working with document libraries. The most common being the error message:

’The document could not be opened for editing. A Microsoft SharePoint Foundation compatible application could not be found to edit the document.’

The error is misleading because like most people you do have an application like Microsoft Office installed that will be able to edit the document in question.

The Problem

Documents are associated with a particular application via the DOCICON.XML file.  More information on this file and how it works in Understanding DocIcon.xml files. In Internet Explorer the browser has the ActiveX control integrated that allows it to marshal the call to the associated application.

Firefox does not include this ActiveX control and reports, although not a very good error message, that there is no compatible applications.

Office 2010 to the rescue

As part of the installation of Office 2010 Microsoft have included a plug-in for Firefox that allows Firefox to work correctly in the form of the FFWinPlugin Plug-in. 

As with the rest of the SharePoint the user experience is almost identical regardless of the browser used.

Not a golden bullet

With SharePoint 2010 support for IE6 was removed, with good reason and to the delight of many UI designers. The problem is a lot of organisations take time to move there desktops, often locked into IE6 because of fixes added to applications to over come IE6 problems.

Getting SharePoint 2010 into these environments is a challenge and using Firefox is one of the olny real options available – short of a desktop refresh. These older desktops will also likely be running older versions of Office.

Unfortunately the Firefox plug-in is provided as part of Office 2010!  Leaving these users with a different experience.  Hopefully Microsoft will see that this Firefox Plug-in is really useful and release it as a standalone installation to make it available to those that can’t yet move to Office 2010 or IE8.

Minor Bug with Office 2010

There is a KB article which details an issue with the Plug-in  when the document library is set to Require Check Out.  http://support.microsoft.com/kb/979634