Facing merge problem in tortoisehg

[Utsavi]

Hello, 

I am beginner in tortoisehg. I want to merge two branches.

For that I write something like this.,

 - "hg config merge-patters"
   to make sure no merge rules are set
 - "hg merge --tool :fail --debug 19"   //19 is my experiment branch
   (i.e. run the merge with --debug option)

and conflict generated and merge done successfully.  

Now when I am doing this by., right click revision->press merge with local and do merge then, conflict is not generated. Why??

And resulted revision (after merge with default branch), is same as default branch.

Why this is so?

Please suggest.

Regards

Utsavi Bharuchwala