Patch Set 1:

By default, GTK has another button ordering than Windows or Mac. But at least on Kubuntu, you should see the same unless you didn't specify the "gtk-alternative-button-order=1" in your ~/.gtkrc-2.0 file (see http://download.eclipse.org/eclipse/downloads/drops/R-3.5-200906111540/eclipse-news-part1.html - Alternate Button Order)
For me, the Cancel button is on the left and the OK button on the right.