Izotope RX8 and Cubase 10.5

I really can’t get RX8 to work in C10.5 using the ‘monitor’ approach. It worked in RX7 but I’m having no joy here. What am I missing? I used to be able to select a section (say 6 bars) of a part, send it to RX, edit it, and then have the option to send it back. The option to send it back is not showing up in RX8. I am running RX8 Standard.

BTW the Guitar DeNoiser is available as a VST3 plugin in C10. What is weird here is that as you open the VST3 RX8 plugin and select a preset setting within the particular plugin, the RX preset menu remains in the center of the plugin. To remove it you have to go to your channel and click on the ‘E’ button which removes the plugin from view, and then click on it again to see the plugin appear without the preset menu. Weird. I haven’t tried the WL option yet…