Course categories list display

If we have many course categories, levels on course categories hierachy or both the list display in the combo will not be optimal. Each level of categories will be separated with a "/" and if we have many levels or just categories with a long name it's possible to not see all informations. That's not very practical  for the selection.

This bug is present when we edit/create a course and also if we want to create a new course category in the selection of the parent category.