In order to support changes in the October 2017 Outlook update from Microsoft the file list in versions of MacroView DMF and Message from 8.4.1317 onward do not by default utilize the entire reading pane area in Outlook. As a result, the standard Outlook search controls may be visible above the file list when viewing the contents of an area in SharePoint.
These controls have no affect when used while viewing a SharePoint location which can be confusing to users, so if you want hide these controls when viewing SharePoint locations you can do so by enabling Roaming Folder Homepages in Outlook.
To enable Roaming Folder Homepages in Outlook add or edit the following DWORD registry value and set it to 1
For more information on the changes to the Home Page feature support in Outlook and more detail on the above workaround, see Outlook Home Page feature is missing in folder properties