Currently the plugin poll the entire stream for changes, even if sub-path is specified. This results in all projects in a stream to rebuild when only one of them had changed.
The nice improvement would be to be able to pass a directory to the "hist" command using either sub-path or a new parameter. Even better, allow users to specify wild-cards for elements to use to poll for changes.

This could be done by issuing the "hist" command for all elements that match wild cards or by filtering the output of "hist".