It works!! this maybe pretty obvious but I didn't know
All these time I just started beryl-manager from the applications menu and the window borders would disappear.
Now, I start 'beryl' from a terminal and then start beryl-manager and everything works fine.
BTW the lspci o/p showed this:
Code:
00:02.0 VGA compatible controller: Intel Corporation 82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)
My onboard graphics is pretty old and is not supported, but it works ok for me, except if I open too many windows then the above problem occurs again.