Elements collection inside class with @Frame annotation isn't working

[lyubenkov]

Method Elements.getListElement(WebElement el) clears up parent property in el by setting it to null.
That's why the @Frame information is lost in the context if there was one, and there is no call to the GetElementModule.getFrameContext(By frame) method.
As a result all elements in declared Elements collection inside iframe class with @frame annotation couldn't be found in DOM.
Parent property should be saved for all elements inside iframe, because it's necessary to switch into frame to work with internal elements using Selenium.