How to open an inactive dialog window?

Add-ons Development
#1

I’m trying to open an inactive dialog window, that the opener is still getting focused during and also after the new window opens.
Is it possible?

I’ve tried to:

  1. Call opener.focus() immediately, no effect;
  2. Call opener.focus() inside load event handler, no effect;
  3. Call setTimeout(() => opener.focus(), 0) inside load event handler, works but the new window still captures the focus for a sort moment;
  4. Use alwaysLowered=yes, the new window still gets focused and it’s impossible to bring it back to the top of opener.
#2

What do you mean by “inactive”? Do you mean “hidden”? A popunder?

#3

“Inactive” means the window is not focused, just like after calling window.blur().