I have seen sometime I want to go back to old jdeveloper view after messing around jdeveloper and re-arranging lot of development related window.
Simple level of component position back to original can be achieve by going to
Window –> Reset Window to Factory Settings.
However it will not change the sizing of window and few other stuff.
To completely wipe off GUI Setting for jdeveloper go to following directory in
Document Setting or C:/User folder and delete file “windowinglayout.xml” and restart the jdeveloper.