So, do you have a solution? A declicker VST at the end of the FX row? 
what do you mean exaclty? a clicking noise when a VST FX is turned off?
I think you already know that you can turn FX on/off with a pattern command (like 1F01/1F00) without “clicking” the mouse… 
But I guess you mean some sort of noise… do you hear it also in the rendered song?
if switching off an effect causes a click, it’s most likely because you are switching it off while it still has sound playing. you cannot easily avoid such a problem if you don’t wise ly turn off the effect when there is no signal in it.
I had the same problem,
it’s often best to automate the wet mix down, or somehow return it to it’s original sound before turning it off.
If I remember correctly this kind of ramping when turning on/off fx’s is somewhere on the epic todo-list.
For now the best thing is to automate a send or the wet/dry mix on the fx itself.
You can also use a couple of LFO-envelopes to do the ramping very fast for you.
thanks for answers