Yeah, you’re right, it was designed like this. You can’t pick another ball if you’ve already picked one. But you’re not the first person to ask me that, I’ll try to change it
Not sure if you know, but there are actually 2 tricks to do that.
One is to click on place when bouncing ball can’t enter (it’s probably what you referenced to).
However there is also second. The “hack” works by simply clicking on small ball (which will spawn when you move bigger ball). On that place your big ball can’t enter as well + you do not need to create a separated empty space (which may be filled by small ball) which saves lots of your moves in long-term play.
I guess me and maybe bonf will do something similar soon. There are few tactics for this simple game, but sometimes there is just unlucky case when balls are spawning where they should not.