Buy after ex-date of trading rights.....

Based on my experienced, some mother shares price will be up after the ex-date of trading rights.This can be seen as below:
Real Example,
Counter name: MAS (malaysian airlines system bhd)
Counter code: 3786
Reason share price up:
Share price up on 23/02/2010 after the trading rights which is from 11/02/2010-22/02/2010
Conclusions:
Please focus the those counter have announced the rights issues and date of trading rights.
I can suggest you buy after the ex-date of trading rights.