[dotNetRDF-Support] SparqlGUI query does not run after clear and import

[Jacques B. <ja...@do...>]

Hi,
FYI,
I am just starting to use DotNetRdf and noticed something that might be improved to help newcomers.
In SparqlGUI,
If I check "Default graph is union of all graphs option", then Import a file and run a Query everything is as expected.
If I then click the Clear button and re-import the same file then re-running the query returns no results?!
Workaround is to uncheck and then recheck the "Default graph is union of all graphs" option.
Cloned and rebuilt from BitBucket and gives the same behavior.
I could open an issue and try to correct it if you think it would be worthwhile.
Cheers,
Jacques