One of the requirements imposed on the default Ocean theme was to Not Break Stuff. So now adjustments were made to the l&f which would have broken existing applications; the sizing of widgets is the same and everything should just work out of the box; it's just the skin of that l&f that's different (and, I think you'll agree, better) (quoting Chet's original post).

Here are the screenshots of the same exact application under Tiger 5.0_08 and Mustang 6.0_b98:

Digging in the code of the MetalLookAndFeel locates this suspicious entry:

   "PasswordField.echoChar", (char)0x2022,

which appears to be the result of fixing this bug. So, somebody suggested making this change for Metal as well, and now the default echo char is 2 pixels wider...

Don't be alarmed if one of your forms will become a little garbled :)