HTML over the flash object

Many times I've got the troubles with HTML\CSS while the adding flash objects on the sites. Trying to display CSS popup or stuff like that above the flash object drives me crazy. I've tried even to hide the block that contains object to make it works. But to my surprise to solve this issue was very easy - just set the parameter wmode equal to opaque in object description tags. After that HTML on top of the flash starts working well.