DOM mutation events profoundly degrade performance, and that degradation is not reversed by removing the listeners. We can't allow mutation listeners except when they're absolutely necessary, and never for the top-level browser document. Please see https://developer.mozilla.org/en/XUL_School/Appendix_F:_Monitoring_DOM_changes for more information.
DOM mutation events profoundly degrade performance, and that degradation is not reversed by removing the listeners. We can't allow mutation listeners except when they're absolutely necessary, and never for the top-level browser document. Please see https://developer.mozilla.org/en/XUL_School/Appendix_F:_Monitoring_DOM_changes for more information.