fix iframe width styling

Author: softmarshmallow

packages/builder-web-core/widgets-native/html-iframe/index.ts

@@ -139,4 +139,26 @@ export class HtmlIframe extends Container implements IIframeProps {
       attributes: attrs,
     };
   }
+
+  get finalStyle() {
+    const superstyl = super.finalStyle;
+
+    // width override. ------------------------------------------------------------------------------------------
+    // iframe element's width needs to be specified if the position is absolute and the left & right is specified.
+    let width = superstyl.width;
+    if (
+      width === undefined &&
+      superstyl.position === "absolute" &&
+      superstyl.left !== undefined &&
+      superstyl.right !== undefined
+    ) {
+      width = "calc(100% - " + superstyl.left + " - " + superstyl.right + ")";
+    }
+    // ----------------------------------------------------------------------------------------------------------
+
+    return {
+      ...superstyl,
+      width,
+    };
+  }
 }