Issue filter broken for custom fields that are 'remote'
The issue filtering is broken for all plugins that provides a custom queries implementation.
Example... when a plugin creates new tab with customized issue filtering, it may implement new query class that inherits from IssueQuery.
This is because the queries_controller in the def filter is using get_subclass to figure out the actual query requesting values for the filter. The get_subclass is called on Query class and it uses subclasses to check if requested class is a Query. Unfortunately subclasses return only direct subclasses.
This way, it is not possible now do customize any existing query class and all plugins that do so stopped working.