A user reported (and I have confirmed) that when using Firefox within a Mac environment the vertical scroll bar for the Slicer visualization is not present.
I have one thing needs to confirm with you. Has the user move the cursor upon the slicer visual? If we do not move the cursor upon the slicer, the vertical scroll bar will not appear.
Thanks for responding.
I confirm this anomaly is occurring this morning.
I am using Firefox version 53.0