How to clear dataset class ?

I load a dataset from a gui. When I close the gui the dataset is not cleared. The command 'whos' gives an empty response but the command 'clear classes' generates the message

'Warning: Objects of 'dataset' class exist. Cannot clear this class ...'

Is there an command that can clear the dataset ?

Answer 1

[Walter Roberson]

See http://www.mathworks.co.uk/matlabcentral/answers/56931-more-oop-weirdness-cannot-clear-class

Answer 2

[Rob L]

Thanks for that Walter.