For better results, click on the name of the game and not the launch game button. Wait for the page to load completely. Give it just a moment and then finally click on launch game. I have noticed that if you have a background image set for your page you'll have less issue if you wait for that image to load before clicking on the launch button. If you wish to replicate the issue load a game normally, then open a different game in another window. If you immediately reload the first page you had open it will most likely take you to the window of the second one you opened. It's a minor annoyance, but if you aren't hammering the launch button you should experience this less. It doesn't mean it will never happen if you follow the steps I suggested. So if you get taken to the wrong game, exit and load the game you want and you'll be inconvenienced for the whole ten second it took to correct the issue.