Thank you so much! The bug with Apple's layout was the main thing stopping me from really using Dvorak. I was afraid I had to give up hope on using Dvorak regularly, but now I can switch tabs in Safari without changing layouts. This is just what I needed. Sadly, it isn't perfect, because once in a while, Command-Shift-] in Safari will increase the text size (like Command-Shift-+) instead of changing the tab. But this doesn't happen every time, and usually doesn't happen when I open the Window menu first. Otherwise, this layout has worked fine for me.

By the way, two more little things for the developer: when I open the layouts in Ukulele, it tells me there are some control key combinations missing and offers to add them. Also, there is a typo in the readme: when saying the two possible paths you can install it to, you say "blah OR/ blah" instead of "blah or blah". Just tiny things you might want to look into.