Filtering by document title in children view filters by document reference instead of title

How to reproduce:

• create a page under Sandbox, for example, called "Page-under-Sandbox"
• type some content, save the page
• edit the title of the page and replace the dashes by white spaces, resulting in "Page under Sandbox"
• go to the children view of Sandbox (from the page menu)
• in the table, in the document title filter, type "Page un"

Expected results:

• the page created above is found as a result

Actual result:

• the page created above is not found as a result

However, if the typed filter is "Page-un" or only "Page", the created page is found as a result.

A couple of important consequences of this:

• whenever the slug page naming strategy is used, it's impossible to search children with multiple words (like in the example above), and in general search will be poor (special characters will not be properly searched for)
• if the word that is searched in the document title filter is found in one of the names of the parents of a page, that page will appear as a result of the filter even if its title displays nothing that would make it a result of the search.
• there is incoherency with the page index table, where search in the document title column seems to search properly