[Bug Report] Fullscreen v-dialogs close when clicking external v-snackbar or v-overlays

[Hdbcoding]

Environment

Vuetify Version: 2.0.15
Last working version: 1.5.18
Vue Version: 2.6.10
Browsers: Chrome 76.0.3809.132
OS: Windows 10

Steps to reproduce

Open a fullscreen v-dialog. Trigger an v-snackbar which is not within the open v-dialog to show a message. Click on a close button within the v-snackbar to dismiss the v-snackbar.

e.g.:
<v-dialog fullscreen>open this</v-dialog> <v-snackbar>open, then click on this</v-snackbar>

Expected Behavior

The v-snackbar closes, but the v-dialog stays open.

Actual Behavior

Both the v-snackbar and the v-dialog close.

Reproduction Link

https://codepen.io/hdbcoding/pen/KKPQVzE

Other comments

This same behavior also happens for v-overlays which are outside of the open fullscreen v-dialog.

This bug does not occur when opening an external v-dialog. If you open a fullscreen v-dialog, then open another v-dialog which is not within the first fullscreen v-dialog, you can close the second v-dialog without immediately closing the first.

This bug also does not occur for non-fullscreen dialogs. If the initial dialog is not fullscreen, you can open external overlays and snackbars on top of it, and close them, and it will not close the initial dialog, as expected.

The codepen shows the results of opening a dialog with options for fullscreen or persistent. Within the dialog you can open and close snackbars, overlays, and dialogs that are either within the html of the open dialog or outside of it. Importantly, this shows that persistent is not a workaround for this issue.

[jacekkarczmarczyk]

Duplicate of #7310