Function isEmpty

include/eepp/ui/models/modelselection.hpp:26–29

		return mIndexes.size();
	}
	bool isEmpty() const {
		Lock l( mMutex );
		return mIndexes.empty();
	}
	bool contains( const ModelIndex& index ) const {
		Lock l( mMutex );
		return std::find( mIndexes.begin(), mIndexes.end(), index ) != mIndexes.end();