Steps to reproduce:

1. Open a new relationship editor using "Add relationship" button
2. Select Artist as target type (or any type that has many relationship types)
3. Click in the "Relationship type" autocomplete field
   At this stage, a list of relationship types with comments will show up (usually recent items, then the full indented list of possible relationship types)
4. Try scrolling the list with a mouse wheel
   At this stage, you should notice that it often jumps to the previously focused item, the first of the list by default.

Notes:

• It works fine if you use the scrollbar instead of the mouse wheel.
• The same wrong behavior happens in the autocomplete field for the target entity ("Artist" in this example).
• I have not been able to reproduce it outside of the relationship editor;
  For example, the release group field in the release editor works just fine even though it shows type and artists on a separate line.