The handles are added so that at any point you can make the dialog resizable
by this call:

$("#myDiv").data("resizable.dialog", true);

As far as changing the cursor, or hiding the handles, either of these can be
accomplished with css. The dialog has the class

ui-dialog

and the resize handles have the class

ui-resizable-handle

Finally, when resizing on the dialog is disabled, the dialog (ui-dialog)
will also have the class

ui-resizable-disabled

If the cursor isn't changing for you currently, it could be a theme bug. If
that's the case, please let us know which theme, so we can update it.
Thanks.

- Richard