Why can't I access iCloud tabs on Webkit Nightly?

I recently switched to Webkit Nightly as my primary web browser, to take advantage of some plugins I downloaded and hope to create for Sublime Text 2. After switching, I noticed that my iCloud tabs button was greyed out, and when I tried to refresh it (Take it out of the toolbar and put it back in), it wasn't an option to add back. Anyone know whats going on?