I verified this.

Added a new String() field summary to the issue class in the classic
tracker created by demo.py:

I used the below but without indexme='yes' the first time through.

issue = IssueClass(db, "issue",
                assignedto=Link("user"),
                keyword=Multilink("keyword"),
                priority=Link("priority", quiet=True),
                summary = String(indexme='yes'),
                status=Link("status"))

Added entries for summary to issue.item.html and issue.search.html
files copying the tal/html entry for the title param in each file.

When I added "zoot zorch" as the summary content for one issue, I could
find that same issue by looking for zoot using the summary field search
box in issue.search.html. However I could not find it using the all text
search nor could I find it using the text search at the top right of the
web page.

I then edited schema.py and added indexme="yes" as shown above.
Ran a reindex using:

  python roundup/scripts/roundup_admin.py -i demo reindex

searched for zoot using the all text search and the top right hand
search box. Both of them returned the correct issue.

Changed customizing.txt indicating 'no' is the default value.

See: f74300d1494e