At 1:48 of the first period in the Stars/Capitals game, Washington requested a Coach's Challenge to review whether Devin Shore interfered with Capitals goaltender Braden Holtby prior to Dallas' goal.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee determined that the actions of the Washington player caused Shore to contact Holtby before the puck crossed the goal line. The decision was made in accordance with Note 2 of Rule 78.7 (ii) which states, in part, that the goal should be allowed because "the attacking Player was pushed, shoved or fouled by a defending Player causing the attacking Player to come into contact with the goalkeeper."
Therefore the original call stands - Good goal Dallas Stars.
Since the Coach's Challenge did not result in the original call being overturned, the Washington Capitals forfeit their time-out.