When selecting the page for a link in editor, Solr/Search does not work as expected

We observed that when selecting the page for a link in the WYSIWYG editor, the search will only suggest a page if a full word is used as query (otherwise it works very smoothly, great stuff). Here is an example of a failed search:

search-failed

In this case, the longer search query is successful:

search-successful

We need to also match partial words - how can we achieve this? Many thanks in advance.