I've read through all the suggestions - because have same problem, this is how these tables are designed - and it looks like important detail was overlooked. His window goes 5" BELOW the table bottom. The suggestion with piece of wood under the window might work. You can then bolt another piece of wood vertically on that board, so that it would reach the table, or come up with some Z-brackets. I'm only afraid that the other end will still wobble a little, because it is only supported in the middle. Don't know what to do with this other end.