Ya we are aware of the bug and unfortunately there seems to be no solution to the bug. But in reality whatever task you perform like as you said while making a new line- the other line gets erased; it actually doesn't happen. For some seconds it looks like the text has been erased but that's not the case. Just continue typing in the normal manner and everything will be fine. If you want to check whether what you have typed has been erased or not, just take your mouse cursor at the end of the posting area and click over there a couple of times. You will see that everything is normal. You can also click at the affected area a few times and then everything will look normal. Even if it doesn't look normal- it actually is.
We sincerely apologize to all our members for the bug. I guess we have to stay with it. We still request you to be with us and support us.