[PD] make sections sortable

- allow to sort loft sections by dragging: https://forum.freecadweb.org/viewtopic.php?f=19&t=50222

- fix bug of uninitialized options: https://forum.freecadweb.org/viewtopic.php?f=19&t=50221

- use better code for the context menu of the listWidget (the same we use in other placed of PD)

- add missing tooltip for mirror feature

src/Mod/PartDesign/Gui/TaskLoftParameters.cpp

@@ -77,12 +77,20 @@ TaskLoftParameters::TaskLoftParameters(ViewProviderLoft *LoftView,bool /*newObj*
     connect(ui->checkBoxUpdateView, SIGNAL(toggled(bool)),
             this, SLOT(onUpdateView(bool)));
 
+    // Create context menu
     QAction* remove = new QAction(tr("Remove"), this);
-    remove->setShortcut(QString::fromLatin1("Del"));
+    remove->setShortcut(QKeySequence::Delete);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 10, 0)
+    // display shortcut behind the context menu entry
+    remove->setShortcutVisibleInContextMenu(true);
+#endif
     ui->listWidgetReferences->addAction(remove);
     ui->listWidgetReferences->setContextMenuPolicy(Qt::ActionsContextMenu);
     connect(remove, SIGNAL(triggered()), this, SLOT(onDeleteSection()));
 
+    connect(ui->listWidgetReferences->model(),
+        SIGNAL(rowsMoved(QModelIndex, int, int, QModelIndex, int)), this, SLOT(indexesMoved()));
+
     this->groupLayout()->addWidget(proxy);
 
     // Temporarily prevent unnecessary feature recomputes
@@ -109,6 +117,10 @@ TaskLoftParameters::TaskLoftParameters(ViewProviderLoft *LoftView,bool /*newObj*
         ui->listWidgetReferences->addItem(item);
     }
 
+    // get options
+    ui->checkBoxRuled->setChecked(loft->Ruled.getValue());
+    ui->checkBoxClosed->setChecked(loft->Closed.getValue());
+
     if (!loft->Sections.getValues().empty()) {
         LoftView->makeTemporaryVisible(true);
     }
@@ -250,6 +262,27 @@ void TaskLoftParameters::onDeleteSection()
     }
 }
 
+void TaskLoftParameters::indexesMoved()
+{
+    QAbstractItemModel* model = qobject_cast<QAbstractItemModel*>(sender());
+    if (!model)
+        return;
+
+    PartDesign::Loft* loft = static_cast<PartDesign::Loft*>(vp->getObject());
+    std::vector<App::DocumentObject*> originals = loft->Sections.getValues();
+
+    QByteArray name;
+    int rows = model->rowCount();
+    for (int i = 0; i < rows; i++) {
+        QModelIndex index = model->index(i, 0);
+        name = index.data(Qt::UserRole).toByteArray().constData();
+        originals[i] = loft->getDocument()->getObject(name.constData());
+    }
+
+    loft->Sections.setValues(originals);
+    recomputeFeature();
+}
+
 void TaskLoftParameters::clearButtons() {
 
     ui->buttonRefAdd->setChecked(false);

src/Mod/PartDesign/Gui/TaskLoftParameters.h

@@ -60,6 +60,7 @@ private Q_SLOTS:
     void onClosed(bool);
     void onRuled(bool);
     void onDeleteSection();
+    void indexesMoved();
 
 protected:
     void changeEvent(QEvent *e);

src/Mod/PartDesign/Gui/TaskLoftParameters.ui

@@ -98,7 +98,14 @@
     </layout>
    </item>
    <item>
-    <widget class="QListWidget" name="listWidgetReferences"/>
+    <widget class="QListWidget" name="listWidgetReferences">
+     <property name="toolTip">
+      <string>List can be reordered by dragging</string>
+     </property>
+     <property name="dragDropMode">
+      <enum>QAbstractItemView::InternalMove</enum>
+     </property>
+    </widget>
    </item>
    <item>
     <widget class="Line" name="line">

src/Mod/PartDesign/Gui/TaskMirroredParameters.ui

@@ -40,6 +40,9 @@
    </item>
    <item>
     <widget class="QListWidget" name="listWidgetFeatures">
+     <property name="toolTip">
+      <string>List can be reordered by dragging</string>
+     </property>
      <property name="dragDropMode">
       <enum>QAbstractItemView::InternalMove</enum>
      </property>