Can I click a click bar through a video FX window?

I have a click bar set up on my second toon with a video FX source over it. It works as expected when I click on it in the second window. I create a video FX viewer on the main screen and tick the repeater radio button.

When I mouseover the viewer I see the cursor in the second window, and the debug console shows the mouse clicks going to the second window, but the clickbar doesn't respond.

Any suggestions? Is it supposed to (not) work?

[lax]

Broadcast inputs, including through Video FX, will not activate any Hotkeys or Click Bar buttons in that window; the inputs go straight to the game.