Redmine

An exemple would be a plugin using select2 (https://select2.github.io/) which add some span elements having a title to the select box and thus get underlined + a help cursor.

I'm not an expert, but changing span[title] to span[cf_title] would fix the issue I see (help cursor at various places), but break the custom field tooltip (as it is the "title" that makes the hovering tooltip appear).

I think the span used for custom fields should be given a class to that this class can be targeted by the css, such as in this sample:

https://jsfiddle.net/BvGHS/452/