diff --git a/painter.js b/painter.js
index b7e6a35..6308472 100644
--- a/painter.js
+++ b/painter.js
@@ -226,9 +226,9 @@ Component({
           doView.css = Object.assign({}, doView.css, newVal.css)
         }
       }
-      (newVal && newVal.url !== doView.url) && (doView.url = newVal.url);
-      (newVal && newVal.text !== doView.text) && (doView.text = newVal.text);
-      (newVal && newVal.content !== doView.content) && (doView.content = newVal.content);
+      (newVal && newVal.url && doView.url && newVal.url !== doView.url) && (doView.url = newVal.url);
+      (newVal && newVal.text && doView.text && newVal.text !== doView.text) && (doView.text = newVal.text);
+      (newVal && newVal.content && doView.content && newVal.content !== doView.content) && (doView.content = newVal.content);
 
       const draw = {
         width: this.currentPalette.width,