Problem: Pushpin control to dock or undock window in ArcMap or ArcCatalog is not visible
The pushpin control to dock or undock window in ArcMap or ArcCatalog is not visible, so the window cannot be hidden or displayed to the side as a tab.
The window has been torn away from the ArcMap or ArcCatalog interface and is not docked, so the window cannot be hidden.
Solution or Workaround
Dock the window. Double-click the title bar of the window to dock it. The pushpin control is now visible.
See the section 'New dockable window controls make it easy to arrange and organize your display' in the 'What's new in ArcMap 10 basics' Help topic and the 'ArcMap: Usability Improvements' video in the Related Information section below.