Case in point; we have Product Version (and Target Version) as required fields when an issue is raised on all our projects, but different projects can have different version numbers. So an issue raised in "Web-based GMS" (with a perfectly valid version number for that project), when moved to "Desktop GMS" becomes invalid because the version number recorded on the issue doesn't exist in the "Desktop GMS" project. The person moving the issue cannot change the version number before the issue is moved, and may well forget to set it once it is moved, and your average developer isn't going to notice in his many hundreds of issues that one is (in effect) missing these two fields until he comes to change the issue (let's say he's making it "More info required", has typed up a long note, and then looses everything he's done because as far as MantisBT is concerned a required field is blank and the developer in question has somehow stopped his web browser from retaining form field data like every other web browser out there does...). It would be simpler all round if when the issue mover has chosen the target project and hit the move button, all the fields which now require valid data were offered for completion.