resizable: disableSelection is not a function

Using the latest trunk versions of core, dialog and resizable I found
that resizable doesn't work without using disableSelection: false/
true. Without you get a "disableSelection is not a function" and the
resizable function does not work.
I.e. it must look like this or else it won't work:
    $("img#image1").resizable({
     handles: "all",
     aspectRatio: true,
        preventDefault: true,
        ghost: true,
        disableSelection: false,
        knobHandles: true,
     stop: function(e, ui) {
     document.getElementById('rsimage1-width').value =
document.getElementById('rsimage1').width ;
     document.getElementById('rsimage1-height').value =
document.getElementById('rsimage1').height ;
     }
    });
What am I doing wrong or is this a bug?