SearchView support.v7。appcompat库问题:默认9补丁的背景不能正确显示。

I'm developing an app with ActionBar using support.v7.appcompat library. The action bar works, the SearchView is shown, the hint shows. The only problem is that the background of the SearchView is not scalling properly. Insead of the usual, it appears big and with the 9-patch black lines. I'm developing an app with ActionBar using supp