Arrows inside box adds wrong connections.

[enomado]

Expected

   ┌────────────┐ 
   │   A  ─────►   B   │
   └────────────┘

Got

┌────┬──── ──┐
│ A  │┼┼┼┤►  B     │
└────┴──── ──┘

formatting is kinda broken, but idea in┼┼