code/Dashboard.php
public function setdefault(SS_HTTPRequest $r) {
		foreach(SiteConfig::current_site_config()->DashboardPanels() as $panel) {
			$panel->delete();
		}
		foreach(Member::currentUser()->DashboardPanels() as $panel) {
			$clone = $panel->duplicate();
			$clone->MemberID = 0;
			$clone->SiteConfigID = SiteConfig::current_site_config()->ID;
			$clone->write();
		}
		return new SS_HTTPResponse(_t('Dashboard.SETASDEFAULTSUCCESS','Success! This dashboard configuration has been set as the default for all new members.'));
	}
public function setdefault(SS_HTTPRequest $r) {
		foreach(SiteConfig::current_site_config()->DashboardPanels() as $panel) {
			$panel->delete();
		}
		foreach(Member::currentUser()->DashboardPanels() as $panel) {
			$clone = $panel->duplicate();
			$clone->MemberID = 0;
			$clone->SiteConfigID = SiteConfig::current_site_config()->ID;
			$clone->write();
		}
		return new SS_HTTPResponse(_t('Dashboard.SETASDEFAULTSUCCESS','Success! This dashboard configuration has been set as the default for all new members.'));
	}
A controller action that handles setting the default dashboard configuration

@param SS_HTTPRequest The current request
@return SS_HTTPResponse