In Metric Viewer when creating a new view it is possible to expand the metrics until they are no longer visible and yet a scrollbar does not show up. If enough metric are expanded a scroll bar will finally show up.
Image 1 shows the metric at the point they all show.
Image 2 shows the bottom metric no longer shows.
Image 3 shows after enough metrics have been expanded and the scrollbar shows.
Release : 20.3
Component : UIM OPERATOR CONSOLE - METRIC VIEWER
Fixed in an update to ump_operatorconsole.zip which will be included in 20.3.3 July update.
Clicking the 'Expand All' will get the scrollbar to show up.
Even with the scrollbar it is possible that some metrics can not be seen unless others are compressed.