sidechain with waves plugins

So i have an issue where the sidechain button on Waves C1 SC compressor is not visible.
YES It is a vst3.
It used to be there before cubase vers 8 (eg cubase 7).
It has been bugging me since cubase 8 so thought i would finally ask.

it is there on C6 multiband but not on c1 and a few others. They are all vst3 and it used to be there

see photo for the activate sidechain button

Don’t use the -sc version.