Screen does not disappear and freezes when user clicks back, instead of on walkthrough

[Nitro187]

When there is a walk through screen up, and the user clicks back, instead of on the actual walk through... the current walk through screen stays on top, and does not disappear, but also makes it impossible for a user to now exit that walk through, as you cannot tap on it - it just sits there... forcing a user to have to now close the entire app to continue.

I was able to circumvent this, by adding a "beforeLeave" event that will close the active window, but if the user clicks the back button just before the walkthrough screen pops up, then the walkthrough screen comes up, and the beforeLeave event triggers before the screen pops up, which means it doesn't close it.

EXTREMELY frustrating, cause it renders the app useless until they force-closes it.

Is there something I can do, in order to either block users from clicking on anything before the walkthrough shows up... or instantly make the walkthrough window popup, making it impossible for a user to click on the 'back' button, and also - disable the back button until the walkthrough is done?