When Sheets overlap, they may share Notes and Relations. These are the "linking pins" between Sheets and may play an important role in synthesizing your knowledge and ideas.
To visualize Notes that are shared by two sheets, highlight or select one sheet in the tree's Sheets branch and open the Sheet Overlap window (menu item [Search]|[Overlap] or Ctrl+O). Then click on one of the Sheets in the Sheets' column to see which Notes they have in common, in the Notes' column.
From the Notes column in the Overlap window, you can drag Notes and drop them on any Sheet in the tree or in an open Sheet window.
You can change the dimensions and the position of the Sheet Overlap window. It will be saved and shown in that same way the next time you open the Sheet Overlap window, including the time you start a new session.