i facing the strange file permission situation in my kubuntu environment(KDE) for editing file using particular application.

i using the "kate" to create the file (a.php, b.php) it set permission 664. using the "kompare" i update the content of a.php to b.php the prmission of b.php is changed to 600

both application are running in same user. please provide the solution for my problem

$ll
drwxrwxr-x 5 praveen praveen 4096 Jul 27 14:59 ./
drwxrwxrwx 64 praveen root 4096 Jul 20 15:00 ../
-rw-rw-r-- 1 praveen praveen 3 Jul 27 14:59 a.php
-rw-rw-r-- 1 praveen praveen 3 Jul 27 15:00 b.php

$ll
drwxrwxr-x 5 praveen praveen 4096 Jul 27 14:59 ./
drwxrwxrwx 64 praveen root 4096 Jul 20 15:00 ../
-rw-rw-r-- 1 praveen praveen 3 Jul 27 14:59 a.php
-rw------- 1 praveen praveen 3 Jul 27 15:00 b.php

$ ps aux | grep kate
praveen 11499 11.4 2.1 259036 88132 ? Rl 15:08 0:54 /usr/bin/kate -b

$ps auw | grep kompare
praveen 11446 2.7 2.0 568156 82652 pts/1 Sl+ 15:05 0:00 kompare
i also tried by using umask suggested by running in termal not working that also.

Thanks in advance