weird scrollbar appear

[vortechron]

Description

multiple scrollbar when stacking modal.

Steps to reproduce

1. open first modal
2. open second modal while first modal still active
3. close second modal
4. now we can see scrollbar appear right after i close second modal

[vortechron]

for those who face this issue can follow my current temporary fix:

just toggle html and body overflow to hidden on close and active.
hidden on active, auto on close

this will remove scrollbar that appear when you try to open multiple modal

[service-paradis]

A fix is needed in the modal component method beforeDestroy:
https://github.com/buefy/buefy/blob/dev/src/components/modal/Modal.vue#L221

Buefy should only remove is-clipped if thee closing modal is the last opened one.