Start plugin processBlock without signal

I found out that in Logic Pro X my plugin effect coded in JUCE does not start processBlock() if there is no signal. My plugin is signal generator, but I want to keep it as an effect (no instrument).
So now to start processBlock I need first throw something (some audio region) on the track, then click “play”, and then my plugin processBlock is started, and only then I can remove audio region.
Isn’t it possible to start processBlock just from host with play button?

I guess checking ‘Plugin is a Synth’ in the project settings might be enough to solve this.

No it makes my plugin to be instrument. I want to keep it as an effect.

AFAIK this is not possible with an effect. Maybe it helps to activate monitoring in Logic, you might also need an input for the track, you could choose a virtual audio device like soundflower to make sure you get absolute no input (or to circumvent this, clear your buffer what you already do I guess).