When using XML Tagger, XML Folding tagger with XML text document, the folding tagger freezes the UI while typing.
Generally in Visual Studio, the XML Folding tagger is processed in background while in SyntaxEditor this is done on the UI thread.
Several optimization options might be applied:

    - process xml folding in background

    - process folding similar to process search while typing - a period of inactivity time is needed to invalidate the search / folding

   - caching - if the edit does not change the folding configuration, no processing and redrawing of folding is required

  - some parts for extracting tooltip content and folded content should be optimized