Drag-and-drop is offset inside dialog if page is scrolled before opening dialog

[pmilic021]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

After scrolling the page and then opening dialog, any drag-and-drop list in the dialog component should work properly.

What is the current behavior?

The drag-and-drop list's drop placeholder is offset aprox by the amount scrolled before opening the dialog.

What are the steps to reproduce?

I came across an example of this while looking for possible solution prior to making this issue:
@cisasteelersfan made it in one other ticket (that issue is not the same as this one!)
#13508 (comment)

What is the use-case or motivation for changing an existing behavior?

It is pretty common use case to have drag-and-drop in a dialog

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

7.0.2

Is there anything else we should know?

[belerofont]

I have the same issue in 7.1.1 Angular Material.

[denkerny]

@crisbeto hi, it would be nice to hear something, it is very important, thx

[pmilic021]

@kernyden If it helps you, as a temporary workaround, I forced top to be 0 (usually it is set to the -scrollOffset before opening dialog):

.cdk-global-scrollblock {
    top: 0 !important;
}

This way there won't be no offset in drag and drop, but opening a dialog will look a bit ugly.

[denkerny]

@pmilic021 no, it hasn't helped me, this thing reproduces not only on modal, it happens with lists have scroll.