So I went to the game last night, and sat up on the club level instead of my usual RF seats. About the third inning, I noticed a change at the ballpark.
Part of the problem with the Josh Hamilton HR that was ruled a double back on May 19 was that the 2nd wall -- about four or five feet behind the main wall -- was painted dark green, the same color as the front wall. The umpire said something to the effect that he "saw the ball hit green, so it didn't go out."
However, the 2nd wall is now painted black. I went back through some highlights on texasrangers.com, and it appears that between May 20 and June 5, the Rangers went and painted the top of the 2nd wall black everywhere that it could be seen from the field. I am guessing that took place during the road trip from 5/24 to 6/3.
I took some pictures with my cell phone, but they aren't really clear enough... go to texasrangers.com and look at Hamilton HR highlights on May 19 and June 5 and you'll see the difference.
Kudos to the team for making a change to prevent this from happening in the future. And please note that I am taking full credit for it. ;-) see My Comment on the subject. (Note that something is broken and I can't link to that specific post, just the discussion. Trust me, I suggested they paint it differently about halfway down that thread.)