Fix GUI crash due to outdated spells list

apps/openmw/mwgui/container.cpp

@@ -124,6 +124,8 @@ namespace MWGui
         if (targetView)
             targetView->update();
 
+        MWBase::Environment::get().getWindowManager()->getInventoryWindow()->updateItemView();
+
         // We need to update the view since an other item could be auto-equipped.
         mSourceView->update();
     }

apps/openmw/mwgui/inventorywindow.cpp

@@ -309,6 +309,9 @@ namespace MWGui
 
     void InventoryWindow::updateItemView()
     {
+        if (MWBase::Environment::get().getWindowManager()->getSpellWindow())
+            MWBase::Environment::get().getWindowManager()->getSpellWindow()->updateSpells();
+
         mItemView->update();
         mPreviewDirty = true;
     }
@@ -614,6 +617,9 @@ namespace MWGui
         mDragAndDrop->startDrag(i, mSortModel, mTradeModel, mItemView, count);
 
         MWBase::Environment::get().getMechanicsManager()->itemTaken(player, newObject, count);
+
+        if (MWBase::Environment::get().getWindowManager()->getSpellWindow())
+            MWBase::Environment::get().getWindowManager()->getSpellWindow()->updateSpells();
     }
 
     void InventoryWindow::cycle(bool next)

apps/openmw/mwgui/spellwindow.cpp

@@ -79,7 +79,8 @@ namespace MWGui
                 break;
             }
         }
-        assert(it != store.end());
+        if (it == store.end())
+            throw std::runtime_error("can't find selected item");
 
         // equip, if it can be equipped and is not already equipped
         if (!alreadyEquipped