when the available space changes, recompute the columns
when the available space changes, recompute the columns

kactus-io/kactus,gengjiawen/desktop,kactus-io/kactus,desktop/desktop,gengjiawen/desktop,say25/desktop,artivilla/desktop,kactus-io/kactus,j-f1/forked-desktop,j-f1/forked-desktop,shiftkey/desktop,desktop/desktop,hjobrien/desktop,artivilla/desktop,BugTesterTest/desktops,say25/desktop,desktop/desktop,say25/desktop,gengjiawen/desktop,j-f1/forked-desktop,hjobrien/desktop,hjobrien/desktop,shiftkey/desktop,kactus-io/kactus,hjobrien/desktop,j-f1/forked-desktop,artivilla/desktop,BugTesterTest/desktops,gengjiawen/desktop,BugTesterTest/desktops,say25/desktop,shiftkey/desktop,artivilla/desktop,shiftkey/desktop,BugTesterTest/desktops,desktop/desktop