I'm trying to look for elements by xpath with Selenium's WebDriver:
WebElement element1 = driver.findElement(By.id("someID"));
List<WebElement> xPathElements = element1.findElements((By.xpath("//span[@class='someClass']")));
It has got nothing to do with Selenium, it is the way xpath works.
If you have something like //elem xpath will located anywhere in the document. But if you want to search for an element relative to another element or rather a descendant then you have to use a '.' or a dot like .//elem.