About Schema Validation
If a BizTalk Editor extension provides an ISchemaValidator object, the framework will invoke ISchemaValidator.ValidateSchema when the user invokes the Validate Schema command, or during compilation when the user builds the BizTalk project containing the schema. The extension usually validates the custom properties, and can return error messages as an array of IValidationInfo objects. The error messages are displayed in the Visual Studio Task List window, along with errors returned from BizTalk Editor compiler.