By the way - when I "upgraded" (ha ha ha) to 10.9, I noticed new behavior with the Relay Browser.
- My system default browser is Safari
- KoLmafia's Relay Browser is set to use Firefox
- When I click on the Relay Browser button, Firefox starts - and shows its home page - and the Relay Browser opens in Safari.
- I close that page in Safari.
- When I click on the Relay Browser button a second time, Firefox shows me KoL, as usual.
And from then on, the Relay Browser successfully opens in Firefox for me.
I was unable to discern which browser you were using in your video.
- What is your system default browser?
- What browser do you select in the Relay Browser settings, if any?
There definitely is something wonky about 10.9. I've considered debugging a bit to see what is different to make it open the Relay Browser in the wrong browser, but since I can get it to work correctly by simply clicking the button twice, I haven't been motivated. But, I'll take a look, now that I have read this thread, and see if I can find what is different about launching the browser in 10.9.
Perhaps clicking the Relay Browser button twice will work for you, too, rather than actually opening up two instances of KoLmafia.