Use json for value check.

src/Squidex/app/framework/angular/forms/iframe-editor.component.ts

@@ -24,7 +24,8 @@ export class IFrameEditorComponent implements ControlValueAccessor, AfterViewIni
     private windowMessageListener: Function;
     private callChange = (v: any) => { /* NOOP */ };
     private callTouched = () => { /* NOOP */ };
-    private value: string;
+    private value: any;
+    private valueJson: string;
     private isDisabled = false;
     private isInitialized = false;
     private plugin: HTMLIFrameElement;
@@ -69,7 +70,10 @@ export class IFrameEditorComponent implements ControlValueAccessor, AfterViewIni
                     } else if (type === 'valueChanged') {
                         const { value } = event.data;
 
-                        if (this.value !== value) {
+                        const valueJson = JSON.stringify(value);
+
+                        if (this.valueJson !== valueJson) {
+                            this.valueJson = valueJson;
                             this.value = value;
 
                             this.callChange(value);
@@ -85,8 +89,9 @@ export class IFrameEditorComponent implements ControlValueAccessor, AfterViewIni
         return this.sanitizer.bypassSecurityTrustResourceUrl(this.url);
     }
 
-    public writeValue(value: string) {
+    public writeValue(value: any) {
         this.value = value;
+        this.valueJson = JSON.stringify(value);
 
         if (this.isInitialized && this.plugin.contentWindow) {
             this.plugin.contentWindow.postMessage({ type: 'valueChanged', value: this.value }, '*');