Good work and thanks for sharing!

IMO, answering the pseudo category '--all--' among regular categories was really a design mistake of Pharo 3.0 and should better be reverted.

Message #categories has been designed as a compatibility layer, but it is not really compatible.

The current workaround is to replace it with a new alternate message #realCategories.
If we have to patch each and every external package (not counting base image patches like https://pharo.fogbugz.com/f/cases/13093/File-Out-save-each-method-twice-From-Nautilus-browser-package-menu-or-class-menu)�� this is kind of ruining the idea of compatibility and gives extra work to everybody and un-necessary break compatibility with Squeak.