I solved the problem with gone shutdown button (MATE desktop)

In the September 2015 I have found a problem in MATE desktop environment.
The problem was: shutdown button gone from the MATE's main menu.

exec ck-launch-session mate-session

To fix this quickly I created the shuter project.

Today I suddenly found a solution. I fixed the problem by replacing the next line

exec ck-launch-session mate-session

with the another one:

exec mate-session

in the ~/.xinitrc file.

exec mate-session

 Start sessions of MATE properly!