Check what you see in the Acrobat window against the border properties in the Properties Editor (or Viewer)

For a selected border, the Properties Editor (or Viewer) shows:

• The selected border icon (in the left pane)
• Number of borders selected
• Object and border swatches
• Trap direction (the potential for a trap appears as )
  The trap direction is blank until you set the trap direction using the PDF Trap Editor.
• Neutral density
• Color separations for adjacent object (CMYK percentages, spot colors)