Set the tree widget as focus proxy of the tree property browser

Makes the focus go to the tree widget when set on the property browser,
since it's not very helpful for it to stay on the property browser
widget.

Change-Id: I7b2a686e37d7a2693ec98133f3a51743aadf7cb4
Reviewed-by: Jarek Kobus <jaroslaw.kobus@digia.com>

Author: bjorn

qtpropertybrowser/src/qttreepropertybrowser.cpp

@@ -471,6 +471,7 @@ void QtTreePropertyBrowserPrivate::init(QWidget *parent)
     m_treeWidget->setEditorPrivate(this);
     m_treeWidget->setIconSize(QSize(18, 18));
     layout->addWidget(m_treeWidget);
+    parent->setFocusProxy(m_treeWidget);
 
     m_treeWidget->setColumnCount(2);
     QStringList labels;