message: drop: reset activeDrops to empty array
diff: @@ -17,7 +17,7 @@ function init (scope) {
  if (interaction.prepared.name !== 'drag') { return; }
  // reset active dropzones
  - interaction.activeDrops = null;
  + interaction.activeDrops = [];
  interaction.dropEvents = null;
  if (!interaction.dynamicDrop) {
  @@ -48,7 +48,7 @@ function init (scope) {
  });
  Interaction.signals.on('stop', function ({ interaction }) {
  - interaction.activeDrops = null;
  + interaction.activeDrops = [];
  interaction.dropEvents = null;
  });
  @@ -206,7 +206,7 @@ function init (scope) {
  interaction.prevDropTarget = null; // the dropzone that was recently dragged away from
  interaction.prevDropElement = null; // the element at the time of checking
  interaction.dropEvents = null; // the dropEvents related to the current drag event
  - interaction.activeDrops = null; // an array of { dropzone, element, rect }
  + interaction.activeDrops = []; // an array of { dropzone, element, rect }
  });
  Interaction.signals.on('stop', function ({ interaction }) {
  