Android StageWebView debugging isn't working

Does anyone use this feature? Is it working?

SDK: AIR 21 SDK & Compiler for Macintosh: 21.0.0.176 SDK & Compiler Download

App descriptor:

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<application xmlns="http://ns.adobe.com/air/application/21.0">
...
<android>
  <webContentsDebuggingEnabled>true</webContentsDebuggingEnabled>
...

USB debugging:

StageWebView AS3:

...
if (StageWebView.isSupported) {
   webView = new StageWebView(true); // false - also StageWebView debugging isn't working
   webView.stage = this.stage;
   webView.viewPort = new Rectangle(0, 0, stage.stageWidth, stage.stageHeight);
   webView.loadURL(url);
}
...

App with open StageWebView launched, but WebView isn't inspected.