There is no way to prevent a log window pop up if an error occurs. It is not much work to change this behavior, but I don’t like the idea. I think that, if there is an error, there has to be a kind of notification.
…. is it possible that after autostart there will be a “auto-call-window-open” setting?
Do yo mean that the call buttons appear on startup? There is no setting at the moment that allows this. Again, if you need an end user UI, then you have to use the Designer, a Web Page or any other tool of your choice that let you create user interfaces.