selenium has this "nice" feature where it can crash sometimes on selection
lists with error "cannot scroll element into view", even though element
is visible on crash screenshots. use move_and_click() instad of click() to
try more often to click on selection lists.
Change-Id: I6625d6f426019d7774cafb8eb1c73e0d203c7649
$d->move_and_click('//table//tr//td[contains(text(), "emergency_mapping_container")]/../td//a[contains(text(), "Edit")]','xpath','//*[@id="preference_groups"]//div//a[contains(text(), "NAT and Media Flow Control")]');
ok($d->find_element_by_xpath('//*[@id="mod_edit"]/div/h3[contains(text(), "Edit Preference")]'),"Edit Window has been opened");