Right now we leave handled as true when we process the WM_MOUSEACTIVATE message, which then prevents us from calling DefWindowProc (which would pass the message to the parent window). We should set handled to false when we process the WM_MOUSEACTIVATE message so we call DefWindowProc.
Created attachment 66238 [details] Sets handled to false in WebViewWndProc while handling the WM_MOUSEACTIVATE message.
Comment on attachment 66238 [details] Sets handled to false in WebViewWndProc while handling the WM_MOUSEACTIVATE message. r=me
Comment on attachment 66238 [details] Sets handled to false in WebViewWndProc while handling the WM_MOUSEACTIVATE message. Committed in r66623 http://trac.webkit.org/changeset/66623