seems the change of VM display properties done in SPICE+VNC feature broke VM editing. A change in Display type field should require VM restart. But if I change it the dialog silently closes on OK (instead of showing list of changes) and it's not even saved
Verified on 3.6.0-12
oVirt 3.6.0 has been released on November 4th, 2015 and should fix this issue. If problems still persist, please open a new BZ and reference this one.