To be honest, we have already tried to address this issue. But the fix candidate didn't provide a stable solution which wouldn't affect the proper functioning of RadChat. I have increased the priority of the issue.
This is a high priority bug which is definitely in our TODO list. However, due to its complexity, I am unable to provide an exact time frame when the solution will be released.
Make sure that you follow this item and thus you will get notified when the status changes.
In order to scroll to the bottom of RadChat, you can use the following code snippet as well. Could you please give a try and see how it works on your end?