Crawled Properties not assigned with column values in SharePoint Online

[Deleted]

in Content search, when trimming down to a specific SharePoint Online site, are custom properties searchable? 

https://protection.office.com/#/contentsearch

I get results that seem to suggest "NO" which leaves me with no recourse to really narrow the search to the items wanted. 

Yet, the documentation seems to suggest that if you have set the property up correctly in the schema, you would be able to use it ... 

Properties marked with a Yes in the Queryable column can be searched.

https://support.office.com/en-us/article/Keyword-queries-and-search-conditions-for-Content-Search-c4...