Previously, if there weren't any linkifiers set, only
non-admins could see the "No linkifiers set." message
below the list header. We do not hide the linkifiers
(when there are some of them) from non-admins, so there
seems to be no reason hide the above message when there
aren't any linkifiers.
We fixed the main issue of this form in CVE-2020-9444, but the audit
done at that time only included links found in rendered_markdown; this
change completes our audit for links with target=_blank anywhere in
the codebase.
We already know which list widget a `<th>`
tag is associated with when we set up the
event handler, so it's silly to read data
from the DOM to find that widget again
when the handler runs.
This commit eliminates a whole class of possible
errors and busy work.
Abhijeet Prasad Bodas
Tim Abbott
Steve Howell
Thomas Ip
Anders Kaseorg