This screenshot contains all 3.
1. It opens below the FX window when the FX is added
2. It appears bottom left instead of centred.
3. There is no option to not have it pop up at all. I'd rather choose to see the UI with the Show UI button than have it appear every time I open the FX window and it's first in the chain or I switch to that FX with mouse click.
Side note : does anyone know why Embed bridged UI is not available on Mac?