Selenium isVisible function returns true for an element that is not visible. Attached is the section of the html that's causing the problem. The element I'm checking has the id=messageBoxIDTitle. It's ancestor with id=messageBoxID (the root of the attached html section) has the class MessageBoxHIDDEN. This is the css for the class MessageBoxHIDDEN: table.MessageBoxHIDDEN, table.MessageBox { display:none; height:0; visibility:collapse; } According to the API documentation: "An element can be rendered invisible by setting the CSS "visibility" property to "hidden", or the "display" property to "none", either for the element itself or one if its ancestors." Thus, as messageBoxIDTitle has an ancestor with display:none, the function isVisible should return false.