Bring up the link dialog (OK greyed out as expected). Drag a link from a browser window into the url field in the link dialog. The link drops correctly, but OK doesn't ungrey: you have to click in the field and type something (like space-backspace) before you can hit OK.
Original problem described for link dialog, but same is true of all input fields in XUL textbox and editable menulist. I tried to connect to JS methods for onpaste, ondragdrop, onchange and nothing seems to work!
Reassigning to XUL:Widgets component.
nsbeta1+/adt3 per the nav triage team.
Nav triage team: nsbeta1-