The DNA Annotator plugin provides an algorithm to search for sequence regions that contain a predefined set of annotations.
Usage example:
Open the Sequence View for a sequence that has annotations. A good candidate here could be any file in Genbank format with a rich set of annotations.
Select the Analyze ‣ Find annotated regions... item in the context menu. The dialog will appear:
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Use the Save regions as annotations... button to store the regions as new annotations to the sequence.