When editing any tiki wiki page in avan.tech, you have three tabs at the top: Edit, Categories, Properties). When in the Edit tab, at the bottom, after the contents editor field, you have:
...but this is not shown when you're in the Categories or Properties tab (or others, if any); yet, if you were to write something in the change description field, this description of the change would be recorded even if you change only the tags in the "Properties" tab. So since this property is relative to any changes made to the page, including metadata (not just content changes), it should be pulled out of the tabs area and made top-level/standalone, so that it makes it clear that you can/should write a history change description when changing the metadata of a page.
As for the "Monitor this page" checkbox... this has two problems:
Shouldn't this checkbox be removed from the page editor form for simplicity, and let the user use the page's menu to subscribe to turn monitoring on/off anyway?