http://build.webkit.org/results/GTK%20Linux%2064-bit%20Release/r109083%20(18907)/fast/selectors/selection-window-inactive-diffs.html Maybe related with the fact that GTK's LayoutTestController::setWindowIsKey is not implemented. I'll skip this test for now.
Punting on this until the WK2 blocker is fixed and the test is unskipped. *** This bug has been marked as a duplicate of bug 81736 ***