In Vp19 the default track height can't be set correctly, but you can change it in the InternalPreference:

The HDR-preview window must be adjusted accurately to its display size (otherwise it displays distorted, this problem is since vp18).
The Histogram can't refresh (in Luminance) its MaxCLL/MaxFALL timely and the 10,000 margin failed; this is new in VP19:
