Hi Richard,
Sorry for the late reply just back from holiday, I have toggled the "Select All" tab in the preview window but makes no difference. If I toggle right or left the preview gives me half the pic in greyscale. "Select All" I would expect full greyscale

Presently I'm not seeing all of your screen grab, only the left hand side, piano player.

What VP and Build number? Over the years some of us have reported this happening to VP. Could be something has being held in memory. Do you have GPU acceleration enabled?

Yeah, this is annoying but realise that it does work, and I'm sure we can all help.

you have to push the button (center circle) not the dropdown list.

you have to push the button (center circle) not the dropdown list.

That will deactivate the FXs according to the DropDown menu. Or have I got that wrong?

I assumed he got accidentally push the button, that's why he doesnt see the FX in the preview

I make the selection in the drop down menu (perhaps left half) and thereafter clicking on the circle switches it on (so you see the effect in the left half) or off (when you don't see the effect at all) [or is that the other way round? I'm not at my editor sat the moment!]. The selection remains permanent until the next time you change it in that drop down menu. My own preference is to tick the FX Bypassed item in the menu so that I can see the effect applied to the whole screen or not at all depending on whether I have clicked on the circle but I very occasionally switch to left or right half if I want an immediate side by side comparison.

Richard