title: How to show a context menu on right click in Qt5.5 qml TreeView
body: <p>I want to show a context menu when right-clicking on Qt5.5 qml TreeView item, but it has clicked signal. How to show a context menu on right click?</p>
  
  <pre><code>    TreeView {
          id: tree_view
          anchors.fill: parent
          model: tree_model
          headerVisible: false
          backgroundVisible: false
  
          TableViewColumn {
              role: "display"
          }
  
          onClicked: {
              console.log("clicked", index)
          }
  
          onDoubleClicked: isExpanded(index) ? collapse(index) : expand(index)
      }
  </code></pre>