I have create a SLOT/SIGNAL but I do not succeed to build. I do not really understand why ?
My header is :
class MyTreeWidget : public QTreeWidget
{
    Q_OBJECT
public:
    MyTreeWidget(MyDeviceMngr& device, PulsMainUI& parent);
    ~MyTreeWidget();
private slots:
    void onCollapsed(QTreeWidgetItem*);
    void onPulsTreeWidgetItemExpanded(QTreeWidgetItem*);
    void onDeleteAction();
    void onAddFolderActionTree();
    void onTreeItemChanged(QTreeWidgetItem* item);
};
My C++ file is
MyTreeWidget::MyTreeWidget(MyDeviceMngr& device, MainUI& parent) :
    m_device(device), w_parent(parent)
{
    TreeBox = new PulsBox;
    setSortingEnabled(true);
    setColumnWidth(0, 400);
    setExpandsOnDoubleClick(true);
    setAlternatingRowColors(false);
    setSelectionBehavior(QAbstractItemView::SelectRows);
    setSelectionMode(QAbstractItemView::ExtendedSelection);
    connect(this, SIGNAL(itemExpanded(QTreeWidgetItem*)),
                     this, SLOT(onPulsTreeWidgetItemExpanded(QTreeWidgetItem*)));
    connect(this, SIGNAL(itemCollapsed(QTreeWidgetItem*)),
                     this, SLOT(onCollapsed(QTreeWidgetItem*)));
}
What is strange is that onCollapsed is not found but onPulsTreeWidgetItemExpanded is found !!!!
here the issue:
Undefined symbols for architecture x86_64:
  "MyTreeWidget::onCollapsed(QTreeWidgetItem*)", referenced from:
      MyTreeWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) in moc_mytreewidget.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [connect.app/Contents/MacOS/connect] Error 1
23:09:20: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project connect (kit: Clone of Clone of Desktop Qt 5.4.2 clang 64bits
When executing step "Make"
