Dirty check in host before setting when using custom events. Fixes #1471.

Author: kevinpschaaf

src/lib/annotations/annotations.html

@@ -262,6 +262,7 @@
     _parseNodeAttributeAnnotation: function(node, n, v) {
       var escape = this._testEscape(v);
       if (escape) {
+        var customEvent;
         // Cache name (`n` will be mangled)
         var name = n;
         // Mode (one-way or two)
@@ -284,6 +285,7 @@
         if (mode == '{' && (colon = v.indexOf('::')) > 0) {
           notifyEvent = v.substring(colon + 2);
           v = v.substring(0, colon);
+          customEvent = true;
         }
         // Remove annotation
         node.removeAttribute(n);
@@ -300,7 +302,8 @@
           name: name,
           value: v,
           negate: not,
-          event: notifyEvent
+          event: notifyEvent,
+          customEvent: customEvent
         };
       }
     },

src/lib/bind/effects.html

@@ -26,7 +26,12 @@
         this.__data__[effect.value] = value;
       }
       var calc = effect.negate ? !value : value;
-      return this._applyEffectValue(calc, effect);
+      // For better interop, dirty check before setting when custom events
+      // are used, since the target element may not dirty check (e.g. <input>)
+      if (!effect.customEvent ||
+          this._nodes[effect.index][effect.name] !== calc) {
+        return this._applyEffectValue(calc, effect);
+      }
     },
 
     _reflectEffect: function(source) {