Comment 37 for bug 239462

Let's get back to basics and look at the purpose of the tooltip: it's to provide useful information about the element the mouse pointer is over, that the user might be about to click on.

If the tooltip display mechanism works properly, the user should only need the tooltip once. After reading and comprehending it, any forced redisplay would only have nuisance value -- providing the user is in control of when the tooltip disappears. Redisplay of the tooltip should only be required if the user makes it pop down before fully comprehending it. So forcing the tooltip to redisplay, even if it isn't obscuring the active element, would be undesirable in most instances as it would still obscure something else.

Point taken about the object being larger than the viewing area. However, I believe the browser should be designed to operate smoothly for those that have learned to use its capabilities, making it efficient to use once learned. If, by using it incorrectly in the first few instances it causes some inconvenience to the user, that would suitably encourage the user to discover how this simple mechanism works: hold the mouse still, read and fully comprehend the tooltip, then move the mouse.

The underlying principle is this: put the browsing experience in the hands of the user, in the simplest possible way, instead of having the browser make arbitrary decisions on his or her behalf -- decisions that the user might not want.