I really dislike how the recent epic -> parent transition has made it much more difficult to search for issues linked to a specific epic from the Issues view. Previously, it was easy to add the Epic Link search criterion and type the name of your desired epic; the list of available epics to pick from (based on the given name) would be limited to Epic-type issues.
Now, it appears that the only way to search for issues by epic is to add the Parent criterion. However, when searching for Parents by name, issues of any type from any project are returned in the results of available Parent filter options. This is a horrible user experience and a big step backwards in the usefulness of Issue searches.
