On the left hand debugger pane it has an area where you can input "Variables" and then it will output the value. I have an array of a user defined datatype and tried entering it in this field to see the value. I'm creating my array from a file and wanted to check that I had parsed everything out correctly.
In the variable field I tried entering something like this at first.
That gave me the invalid expression error, so then I tried entering just
in case the debugger could only handle variables and not expressions, but that gave me the same error.