I have following problem. I run test on Firefox and Chrome. On Firefox test run correctly but on Chrome SauceLabs give a message:
unknown error: Element is not
If you're doing anything complicated in your CSS, Chrome can get confused (this has happened to me) and think that the element you're trying to click is covered by another element even though this is not the case.
One way to resolve this is to help Chrome understand the situation correctly by adding z-indexes (you'll need to add relative or absolute positioning also) to unambiguously place the correct element on top of the other.