This one was quite an anomally so I thought I’d share…
I have a SharePoint sub-site with multiple Document Libraries created with the Basic Page Document Template. These libraries were upgraded from MOSS 2007 to SharePoint 2010. Users with Full Control were able to modify/edit the pages just fine but users with Contributor rights were not able to save changes made to existing content pages. When Contributors tried to save changes made with the WYSIWYG editor, which seems to be a variation of the Content Editor Web Part, they get an browser popup error message that says “Cannot save your changes“.
I went up, down and all around all of the permission configurations on the site, library, parents, etc. but couldn’t see why a user with Contributor rights was not able to save their changes. Also of note: the content rendered ok in IE7 but didn’t render at all for the user in Firefox. I finally ended up deleting the page and tried to recreate it with the affected user’s session using Firefox. That’s when I was given a much better clue. The Content Editor Web Part on the page returned: “A Web Part or Web Form Control on this Page cannot be displayed or imported. You don’t have Add and Customize Pages permissions required to perform this action.”
With that clue, I trekked up to the root site and modified the permission levels for Contributors. Site Actions > Site Permissions > Permission Levels (in the ribbon) > Clicked on Contribute and then checked the “Add and Customize Pages” option. And that did it!