If you implement the workaround posted you will get smooth horizontal scroll but it is at the expense of an important feature of the grid... Locked Columns. If you have ever used a spreadsheet with many columns you will know that most of the time you need to lock at least the first column so that you don't get lost in the sea of cells. With the workaround that won't work.
I added a comment on the issue in the bug system, but I urge others to make sure that this temporary workaround is not a solution to the problem. We all need some better resolution to this issue and it seems that it is likely to stay "Deferred".
Let's not let that happen. Create an account in the Adobe bug system and post your comments at http://bugs.adobe.com/jira/browse/SDK-17880