[repost] Need help activating Changes->(Repository, Incoming) tabs

For some long time I'm trying to enable Repository and Incoming tabs in
Changes tool window.

I never managed to make them work completely although in pre 8.1 idea
versions it used to show something (on very special occasions)

Here is my implementation of CommitedChangesProvider:
http://bitbucket.org/viacoban/hg4idea/src/tip/src/org/zmlx/hg4idea/provider/HgCommittedChangesProvider.java

I'd be very thankful if someone would provide some precise steps in
enabling this functionality in idea 8.1+ or idea9

In exchange I will not say a single bad word about "high quality"
openapi documentation.

Regards,
Victor