For docx4j users who wants to analyze and edit the XML parts of a docx/pptx/xlsx, the attached swing
program DocWin.java will be helpful. (I got sick of the tedium of manually unzipping, opening different
parts in a editor, zipping it back up if needed, etc.) DocWin shows the package's parts on the left, in
a tree reflecting the relationship hierarchy, and on the right shows the contents of the part selected on
the left. XML ...