Vertical position is wrong if page content is longer than window height

[ptheofan]

I really liked this plugin! However, testing it's behaviour for bugs on the demo site revealed an issue that prevents me from using it.
Please have a look at the screenshots to see the issue.

Screenshot before triggering the dialog

Screenshot after the dialog is triggered

as you can clearly see, half the dialog is outside the window.

[voronianski]

@ptheofan yes, there is a problem with long content pages due to browser behavior on transformed and positioned elements..

related demo - http://labs.voronianski.com/test/scaled-positioning.html
some inputs on previous discussions - #7 (comment)

as well as related to #41

[Darkicorn]

One fix is to remove body {overflow: auto;} in avgrund.css thus:

html {
    height: 100%;
    overflow: auto;
}

body {
    height: 100%;
}

Which I found by searching for why window.scrollTo(0, 0) didn't work. There is an explanation on Stack Overflow at JavaScript scrollTo method does nothing?