Prior to 12.3 you were able to create a custom query widget that contained a 'UNION ALL' in the query and the widget would work entirely as expected.
After the release of 12.3 the count function on the bottom of the widget no longer works when the count for returned rows exceeds the number of identified max rows to return. please see this thwack posts for screenshots of what I'm referring to Report on Muted and Unmanaged Entities
Reported this to SolarWinds support under case number 00287445, and they have acknowledged the bug with no timeline for fixing it. In the archive email, it was suggested that I place a feature request for it.
Please vote up to bring this functionality back!