If you ever played multiplayer you probably hate the chat spam so there is a setting (inside of multiplayer settings) that can change the opacity of the chat but in 1.7.2/1.7.5 it ain't workin' boy it changes the black background although it doesn't change the text opacity though so there that.
-mcpboss47
Duplicate of MC-36812 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.