How to set focus on a text view when tree selection changed?

[smartkenny <smartkenny gmail com>]

Hi, all

Searched for a long time but didn't find any hints on this. Here's my 
layout:

-------------------------
|           |           |
| tree view | text view |
|           |           |
-------------------------

When clicked on a tree view row, I am going to change text in text view 
accordingly AND let text view grab focus, so that whenever I press keys 
it put characters into the text view.

I tried to connect "changed" on tree view and grab focus on text view, 
but it didn't work, the focus is still on tree view. So when I press 
keys it doesn't put into the text view.

Can any body please give me a clue how to do this? Thank you very much.

Kenny