It's a very common problem with Poser. You need to reset it to factory standards, (Edit - General Preferences) then when it's all back where it should be, set an UI dot (those little 3X3 balls usually hiding in a corner) With an UI Dot set, all you need to do next time it happens (and it WILL happen again) is to click it and restore your interface. Oh and be sure to NOT place your UI Dots where the window will cover them up next time it goes north-west ;o)

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.