Preferences -> Camera -> 2D & 3D Mouse Wheel Factor Slider Widgets Inoperable
The 2D and 3D Mouse Wheel Factor sliders in the Preferences -> Camera
dialog do not respond to clicks / drags. However, manually entering a value other than "1" (the default) in the accompanying text box appears to have an effect on the (in this case) zoom speed.
Other Preferences sliders (e.g., under Render View) do respond appropriately to clicks / drags.
This issue is experienced on macOS 10.12.6 with ParaView 5.5.2 and 5.6.0-RC2-290.
Current settings and non-functional sliders shown below.