Its due to the way you have the div hidden to begin with, if you notice the g+ tab is not the correct size either. The plugins dynamicly build themselfs based on those initial defaults and in your case when youve customized it to be 0 it starts off 0 and not shown , G+ same reason but it has a min-width inside the iframe ….
You should check your customizations because if you are going to do it that way you likely cannot use this plugin without also reinitializing the Javascript that draws the iFrames making it do it again when the comments are shown …. in other words alot more custom code than just tossing it into a toggle able div
Not really a plugin issue. Sorry
