Going ahead with the switch to tabs. This is a major coding standards change! If any unusual parser bugs show up, check this changeset. Converted all .php, .js, .tpl, .css, and .json files and did basic testing.
table.wrapper td.top-left { width: 37px; height: 28px; background-image: url(../images/window-gif/window-topcorners.gif); background-repeat: no-repeat; }
table.wrapper td.top { height: 28px; background-image: url(../images/window-gif/window-top.gif); background-repeat: repeat-x; }
table.wrapper td.top-right { width: 37px; height: 28px; background-image: url(../images/window-gif/window-topcorners.gif); background-repeat: no-repeat; background-position: -37px 0px; }
table.wrapper td.left { width: 37px; background-image: url(../images/window-gif/window-left.gif); background-repeat: repeat-y; }
table.wrapper td.right { width: 37px; background-image: url(../images/window-gif/window-right.gif); background-repeat: repeat-y; }
table.wrapper td.bottom-left { width: 37px; height: 44px; background-image: url(../images/window-gif/window-bottomcorners.gif); background-repeat: no-repeat; }
table.wrapper td.bottom { height: 44px; background-image: url(../images/window-gif/window-bottom.gif); background-repeat: repeat-x; }
table.wrapper td.bottom-right { width: 37px; height: 44px; background-image: url(../images/window-gif/window-bottomcorners.gif); background-repeat: no-repeat; background-position: -37px 0px; }