TWM: [BUG]: Error when deleting a world in Pharo 4

"ValueNotFound: value a WorldMorph(511705088) [world] not found in Dictionary"
From TWMWorldManager>>#currentWorldName
         ^ worlds keyAtValue: World

There is something weird going on with World switching in general. I wonder if we correctly mapped the Squeak behavior to Pharo. For one thing, there's still the odd flashing between the source and destination world. And now that  I've merged in the TWMWorldAdded announcements, it seems that creating a new world flashed to it, and then right back to the original world. Now here's the crazy part: if you maximize the Pharo window (Mac OS X 10.8.5), the other world appears!

I made a config with the latest code and stashed it on StHub in case anyone wants to have a look at the world switching bug in particular.

Gofer it
        smalltalkhubUser: 'SeanDeNigris' project: 'SeansOutbox';
        configurationOf: 'TilingWindowManager';
        load.
"For some reason, #loadStable above gives a strange error about not finding a package version that it's not even supposed to be loading, but doing the load in a separate statement below works"
ConfigurationOfTilingWindowManager project stableVersion load.