Gaps and Margins
    Gaps and Margins contains controls for adjusting
    margins in a surface or volume montage and margins around tab content.
    All gaps and margins are specified as a percentage of the width or 
    height.
    
      - Window selects the window to which the
      gaps and margins are applied.
      - Montage Gaps sets gaps in surface or
      volume montages.
      - Tab Margins sets margins around the
      edges of tabs.
      -  Match Pixel Size to TopWill adjust the 
      percentage width so that the actual pixel width of left/right margins is
      the same as the pixel height of top/bottom margins.
