When you assign one or multiple tags to a question and then save this question into the question bank; the question bank will automically update its _indexes _so that you can query the question bank by selecting tags and find the right set of questions easily.
However there may be some cases where you would like to add a tag to a question but you don’t want the question bank to index this tag.
For example, let’s image that you would like to add the tag: [Question ID: 1234] to a question.
This Question ID tag will apparently hold a unique ID value for the question. (Most probably this ID value refers to another ID value in another system.)
So we may not prefer the question bank to index this tag. Otherwise the querying interface will show you all the Question ID value that you can pick. This is both a very crowded interface and it does not really help us.
What is New?
That’s why we introduce a new feature: If the tag name stats with an underscore (_), the system will not index this tag.
This feature works the same way for both Question Bank and User Bank.