Just upgraded to 1.4.2 and am finding it to be extremely slow, sometimes unresponsive and hence buggy. Using the latest version of Firefox and finding it extremely difficult to even get a new form created. Many fields will simply not add to the form, but if they eventually do, I cannot edit all of them, for instance the email field. To give you a sense for how long some things are taking. I clicked to add an email field, and it took 20 seconds for the field to actually show up on my form.