To change where Diff Merge displays the merge results and HTML browser panes:
Note: Changes made to this option are saved when you quit Diff Merge.
If you are not merging, Diff Merge does not display a merge results pane. If your contributors do not contain HTML code, Diff Merge does not display an HTML browser pane. However, even if these panes are not displayed, you can still set the option and the changes apply to the subsequent Diff Merge session. That is, if the subsequent Diff Merge session is a merge, the location of the merge results pane is affected, and if you are comparing or merging HTML contributors, the location of the HTML browser pane is affected.