Two rival developers in the fast-gentrifying Dumbo neighborhood in Brooklyn have gone to battle across the lot line of their properties. On one side is David Walentas, the tenacious visionary who helped remake Dumbo as a residential hot spot. On the other is Shaya Boymelgreen, a relative newcomer with deep pockets who has become a  ajor player in the neighborhood in only the last few years.

The two have clashed over projects before, but now their feud has blocked condo buyers in a converted industrial building at 57 Front Street,
owned by Mr. Boymelgreen, from closing on their apartments. And even if
they do close soon, some of them may find something else is blocked -
their views - because Mr. Walentas has vowed to erect a steel barrier
in front of the windows in his rival's building.