don't show the "move layer" button if only one layer exists

GUI/View/SampleDesigner/LayerForm.cpp

@@ -56,11 +56,11 @@ LayerForm::LayerForm(QWidget* parent, LayerItem* layer, SampleEditorController*
         });
     }
 
-    auto* moveButton = new WidgetMoverButton(this, this, 1);
-    moveButton->setToolTip("Move layer up/down");
-    connect(moveButton, &WidgetMoverButton::startingToMove, ec,
+    m_moveButton = new WidgetMoverButton(this, this, 1);
+    m_moveButton->setToolTip("Move layer up/down");
+    connect(m_moveButton, &WidgetMoverButton::startingToMove, ec,
             &SampleEditorController::onStartingToMoveLayer);
-    connect(moveButton, &WidgetMoverButton::finishedMoving, ec,
+    connect(m_moveButton, &WidgetMoverButton::finishedMoving, ec,
             &SampleEditorController::onStoppedToMoveLayer);
 
     auto* showInRealSpaceAction = ActionFactory::createShowInRealSpaceAction(
@@ -69,8 +69,8 @@ LayerForm::LayerForm(QWidget* parent, LayerItem* layer, SampleEditorController*
     m_collapser->addAction(showInRealSpaceAction);
     m_collapser->addAction(chooseColorAction);
     m_collapser->addAction(m_removeAction);
-    m_collapser->addWidget(moveButton);
-    m_structureEditingWidgets << moveButton;
+    m_collapser->addWidget(m_moveButton);
+    m_structureEditingWidgets << m_moveButton;
 
     QColor bckgroundCol = m_layer->color();
     setStyleSheet("QGroupBox {background-color: " + bckgroundCol.name(QColor::HexRgb) + "}");
@@ -99,6 +99,9 @@ void LayerForm::enableStructureEditing(bool b)
 
     for (auto* w : m_structureEditingWidgets)
         w->setVisible(b);
+
+    if (b && m_ec->multiLayerItem()->layers().size() < 2)
+        m_moveButton->setVisible(false);
 }
 
 void LayerForm::updateColor()
@@ -149,6 +152,9 @@ void LayerForm::updateLayerPositionDependentElements()
         m_layouter->removeRow(m_thicknessRow);
         m_layouter->insertValue(m_thicknessRow, m_layer->thickness());
     }
+
+    if (m_ec->multiLayerItem()->layers().size() < 2)
+        m_moveButton->setVisible(false);
 }
 
 void LayerForm::onLayoutAdded(ParticleLayoutItem* newLayoutItem)

GUI/View/SampleDesigner/LayerForm.h

@@ -23,6 +23,7 @@ class LayerItem;
 class SampleEditorController;
 class ParticleLayoutItem;
 class GroupBoxCollapser;
+class WidgetMoverButton;
 
 //! Form for editing a layer
 class LayerForm : public QGroupBox {
@@ -49,6 +50,7 @@ private:
     int m_thicknessRow = -1;
     SampleEditorController* m_ec;
     QList<QWidget*> m_structureEditingWidgets;
+    WidgetMoverButton* m_moveButton;
 };