Code review comment for lp://qastaging/~apinheiro/unity/atk-selection

Well, finally I was able to solve that crashes. It seems that the real problem was with the casting. The last commit add more type checks, and it solves it.

I was able to test it, and also get a initial support with orca, although using this custom orca script:

https://bugzilla.gnome.org/show_bug.cgi?id=643419

For the moment it just expose the selection change on the Launcher.

So now, it is just a normal merge proposal.