Prevent page scrolling while modal dialog is open

[strarsis]

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When the dialog is open, notably in modal mode, it is possible to still scroll the page behind of the dialog. The new and now fairly well supported overscroll-behavior CSS property could be applied to the dialog element in order to prevent scrolling of the page when the inside of the dialog is scrolled (overscroll-behavior: contain).

However, it doesn't seem to work with the dialog element, scrolling inside the dialog will still scroll the page.