EXCEL: Unable to show "xsd" (schema file) after choosing

Hello experienced EXCEL / XML users,

I have received an XSD (schema file) and am trying to load it over

(1) Using "Deloper", "Open Source", "XML Maps"
(2) I selected the XSD file

>> Problem: It does not appear in the "XML Maps" window.

What can be the error?

Regards and thanks for ideas to solve the problem

UserWithQuestion_67067