Display exceptions when the browser background is transparent

[lzm515]

Code:
CefSettings settings = new CefSettings(); settings.windowless_rendering_enabled = true; cefApp_ = CefApp.getInstance(settings); client_ = cefApp_.createClient(); browser_ = client_.createBrowser("xxx.html", true, true); browserUI_ = browser_.getUIComponent();
the background of a browser should be transparent, but it is like this

The background should not be a red and blue gradient