If a custom tag has been defined in the DTD, then you need to add the tag in the tagsAndFilters.json file.
WhitespaceHandlingOff - Preserve whitespaces
in WYSIWYG (For example, <codeblock>).TagsToIgnore- Ignore the tags while doing the
search (For example, <metadata> and <image>).BlockElements- Separate each block element
from another while doing the search (For example, <p> and <div>).For example, if a new tag for white spacing handling off has been defined in xml:space preserve, you need to add the tag in the tagsAndFilters.json file at the following location:
C:/Program Data/Adobe/FrameMaker/17/Preferences/xmlSearch/tagsAndFilters.json.