fix bug: removeListener sometimes not working

[novenn]

removeListener not working in some scenior:

If the element or its parent has already been removed and appended to the DOM again then Object.onload is been called again, and onElementDetectable will be called again

in some scenarios: users want to removeListener before element been removed but when the element been appended to the DOM again, if onElementDetectable is called then addListener function will be called again