Flush Memory Cache
The DTD/Schema | Flush Memory Cache command flushes all cached schema (DTD and XML Schema) documents from memory. To speed up validation and intelligent editing, XMLSpy caches recently used schema documents and external parsed entities in memory. Information from these cached documents is also displayed when the Go to Definition command is invoked.
Flush the memory cache if memory is tight on your system, or if you have used documents based on different schemas recently.