The current version of ArcGIS Monitor does not work well in a vertical context monitor; in the case where you have a 20"/24" wide-angle monitor:
but have it vertical and have the monitor vertical then the navigation at the top becomes inconsistent; and access to the content area gets blocked by the obscured navigation. Now when you try to access content areas such as the ArcGIS Block:
Now you will need the top navigation is gone; the menus have shifted below and the ability to expand/navigate the content tree in the left panel is lost.