Yes, Pro/E has done that forever. It makes no difference what kind of object you open in the first window. If you notice, there will be a message pop up telling you that you cannot close the first window. If you open another object it will come up in the first window.
In Reply to David Haigh:
I just noticed that Creo leaves an empty window open. This is Creo 2-m090. I wonder if other rev's behave like this?
1. Started up Creo.
2. I opened a drawing.
3. From the model tree, selected the top assembly in the drawing and picked open.
4. I switched back to the drawing and closed that window.
5. The screen switches back to the assembly.
But I noticed in the system tray that there are two windows open.
When you hover over it so you see the files names, you see this:
The "Creo Parametric" pick is an empty window. You can't close it.
The pull down inside of Creo show only one window choice.
If I pick a sub-assy from the model tree, and pick open it opens it in the blank window.
I know that because I don't get a third window shown in the system tray, and it now shows this when I hover over it:
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