use curr doc instead of global access to material model

GUI/View/SampleDesigner/MaterialInplaceForm.cpp

@@ -41,7 +41,7 @@ MaterialInplaceForm::MaterialInplaceForm(QWidget* parent, ItemWithMaterial* item
     m_layout->setContentsMargins(0, 0, 0, 0);
     createWidgets();
 
-    connect(GUI::Model::MaterialModelStore::materialModel(), &MaterialModel::materialChanged, this,
+    connect(gSessionData->projectDocument->materialModel(), &MaterialModel::materialChanged, this,
             &MaterialInplaceForm::onMaterialChanged);
 }