title: mousePressEvent of QWidget gets called even though QTabletEvent was accepted
body: <p>In a QWidget derived class object with implemented tabletEvent(QTabletEvent *event) and mousePressEvent(QMouseEvent *event), the mousePressEvent gets called every time tabletEvent gets called with type TabletEvent::TabletPress. According to the <a href="http://doc.qt.io/qt-5/qtabletevent.html" rel="noreferrer">Qt documentation</a>, this should not happen:</p>
  
  <blockquote>
    <p>The event handler QWidget::tabletEvent() receives TabletPress, TabletRelease and TabletMove events. Qt will first send a tablet event, then <strong>if it is not accepted by any widget, it will send a mouse event</strong>. </p>
  </blockquote>
  
  <p>mainwindow.cpp</p>
  
  <pre><code>#include "mainwindow.h"
  #include "tabletwidget.h"
  
  MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
  {
      TabletWidget* tw = new TabletWidget(this);
      setCentralWidget(tw);
  }
  </code></pre>
  
  <p>tabletwidget.h</p>
  
  <pre><code>#ifndef TABLETWIDGET_H
  #define TABLETWIDGET_H
  
  #include &lt;QWidget&gt;
  
  class TabletWidget : public QWidget
  {
      Q_OBJECT
  public:
      explicit TabletWidget(QWidget *parent = 0);
  
  protected:
      void tabletEvent(QTabletEvent *event) Q_DECL_OVERRIDE;
      void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
  
  signals:
  
  public slots:
  };
  
  #endif // TABLETWIDGET_H
  </code></pre>
  
  <p>tabletwidget.cpp</p>
  
  <pre><code>#include "tabletwidget.h"
  #include &lt;QDebug&gt;
  #include &lt;QTabletEvent&gt;
  
  TabletWidget::TabletWidget(QWidget *parent) : QWidget(parent)
  {
  
  }
  
  void TabletWidget::tabletEvent(QTabletEvent *event)
  {
      event-&gt;accept();
      qDebug() &lt;&lt; "tabletEvent: " &lt;&lt; event-&gt;type();
  }
  
  void TabletWidget::mousePressEvent(QMouseEvent *event)
  {
      qDebug() &lt;&lt; "mousePressEvent";
  }
  </code></pre>
  
  <p>The output generated if I use the tip of the pen or press any button of the Wacom Intuos CTH-680S-DEIT is:</p>
  
  <pre><code>tabletEvent:  92
  mousePressEvent
  tabletEvent:  87
  tabletEvent:  87
  tabletEvent:  87
  tabletEvent:  87
  tabletEvent:  93
  </code></pre>
  
  <p>So first the tabletEvent gets called, and even though I accept the event, mousePressEvent gets called anyway. Every following tabletEvent is of type QTabletEvent::TabletMove and the last one is QTabletEvent::TabletRelease. From the <a href="http://doc.qt.io/qt-5/qevent.html#Type-enum" rel="noreferrer">Qt documentation</a>:</p>
  
  <pre><code>QEvent::TabletMove 87
  QEvent::TabletPress 92
  QEvent::TabletRelease 93
  </code></pre>
  
  <p>I have tested this on Mac OS 10.10.3 and Windows 7 with the same result. Is this a bug or am I doing it wrong?</p>
  
  <p>This is tested on Qt 5.4.2.</p>