Annoying Unlisted C++ Code Completion Snippets

Whenever I type a C++ keyword like 'using', autocomplete displays unlisted snippets like 'using :: ;' that are not only useless and annoying, but I am unable to find or disable them in Options.

The only entry for 'using' in Snippets is 'using $name$;' (which is what I want). The indicator is also different for these unlisted snippets, showing a grey dot (instead of a red/orange one). I checked the Qt Creator manual and an entry with grey dot is a 'C++ Keyword', which doesn't seem right for a phrase like

using :: ;

Please tell me how I can find and disable these things. Thank you.