As of JIRA 5.1, the 'Watchers' page is now only accessible via a keyboard shortcut (i.e. '.' -> start typing and select 'watchers'), whereas it should also be accessible from a clickable hyperlink on the 'view issue' page.

Currently, (as correctly documented in our JIRA 5.1 documentation) clicking the hyperlinked number to the right of the 'Watchers' link opens the 'Add Watchers' popup. In JIRA 5.0.7 and earlier versions, clicking this number used to open the 'Watchers' page itself.

Hence, it's no longer possible to access this page by clicking a hyperlink on the 'view issue' page.

You can now only access the 'Watchers' page via a keyboard shortcut (mentioned above) and from an issue listed in the issue navigator (via its cog dropdown list on the right).