Not all the changes are saved on a page without a version summary field if "Make version summaries mandatory" is set to "Yes"

Steps to reproduce:

• Login as a admin
• Hover over "Wiki" and click on "Administer Wiki"
• Click on "Edit Mode Settings"
• Choose "Yes" from the "Make version summaries mandatory" drop-down list and click "Save"
• Click on "WYSIWYG Editor"
• Change a setting (for example delete the "bold" feature from the "Tool Bar" section)
• Click "Save"
• Reload the page

When you change the setting you get a "Saved" message, but if you reload the page you'll notice the setting isn't actually saved. I also noticed that the settings that use radio buttons work.

Tested on Chrome 23, Firefox 16.0.2 and IE 9.