Comment 0 for bug 243520

When a page embeds content that is handled by a plugin, it is possible for the plugin to be instantiated, destroyed, then instantiated again, all during the page load. This can mean that scripted commands to the plugin during the page load can be wiped out without the script noticing.

This problem can occur if script in the page accesses the plugin before the first reflow of the embedding element. This is because we synchronously instantiate the plugin if script tries to access it through the DOM before it has been instantiated. Then, regardless of whether the plugin has been instantiated or not, when the embedding element gets its first reflow, it posts an event to instantiate the plugin to the event loop. When this event is run, the "old" plugin instance is shut down and then a new instance is reinstantiated.