- Go to some page and edit in VE
- Click the "Link" toolbar button, type "Category:" and click a category that appears
The leading colon is correctly added, but the category now appears in red in the dropdown as if non-existent (although it shows up under "matching pages", not "new pages").
Probably, the link inspector should be ignoring/stripping the preceding colon when checking whether the page exists.
Same thing for links to File: pages.