The problem is that button. When you click it it gets selected (or "focused") and other parts of you browser get "unfocused". This is the fix:
It's probably better to make your own buttons from sprites, it's much more flexible. These browser components are a pain to deal with if you want any kind of extended customization.
Also one thing, I simplified you ISO variable and made it a boolean. Also made the event run only once. If you leave your events like that they will run every tick, which will cause much unneeded processing. If your event only needs to run once when specific conditions are met make sure that they don't actually run every tick. It's the same thing as with the problem you posted last time.