Currently, there is no way to clear the "Show new changes starting from..." setting once you click it. The only ways are to a) edit the URL or b) use the back button. Even closing the page and logging out doesn't get rid of this setting.
There should be some explicit way to clear the setting. I was going to suggest that using the Trashcan and the Restore Defaults should do it, but I suppose it's possible that some users will want to keep that setting while perhaps adjusting their filters?