Also make sure to turn on the Show Gates toggle found on the illustration control panel on the left side of the Working Illustration:
Make sure that all these conditions are met in the illustration and gates will appear! Check the gating interface to make sure the gate is drawn on the channels and settings that you expect.
Note: when using colored overlay dot plots, gates can be shown but their statistic will not be shown. Create a support request to alert us if this is important for your workflow.