Q: are you running multiple displays or have an extended desktop?
The Properties editor placement logic is supposed to open to open aligned with the default placement aligned with the bottom right corner of the Design Center if sufficient display space is available. If not then it should open aligned with the bottom left corner of Test Center. We are investigating some cases where extended desktops are returning bounds that are much greater than the physical display. We are hoping to improve the default placement. The net is that the Properties Editor should never auto-position itself where it is off-screen or nearly off-screen. So all info appreciated such as display setup, location of Test Center when you opened the Properties Editor and a screenshot.
Wayne
Genuitec Mobile Team