How to remove "selected" border around GtkButton?

In GTK+, how to remove this dotted border aro开发者_如何学Pythonund a GtkButton, which gets drawn after we click the button?

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This is the "focus" indicator. To get rid of this, remove support for keyboard-controlled focus from the button, like this:

GTK_WIDGET_UNSET_FLAGS(GTK_WIDGET(button), GTK_WIDGET_CAN_FOCUS);