Steps to Reproduce:
  [Step 1] Put glass panes in a line
  [Step 2] Put a tower of glass panes on top of that row
  [Step 3] Put any block beside the tower of glass panes
  [Step 4] Crouch on the row of glass panes and around the tower of panes

 Observed Results:
You can crouch around glass panes that are connected to a block

Expected Results:
You shouldn't be able to crouch around glass panes that are connected to a block

Notes:
You can crouch around glass panes and iron bars that are connected to a block that are on a 2 pixel wide walkway, but if there is 2 panes/bars on top of each-other they both need a block beside each-other to crouch around