Fix invalid cast exception in the spell creation dialog

apps/openmw/mwgui/spellcreationdialog.cpp

@@ -454,10 +454,13 @@ namespace MWGui
 
         mAvailableEffectsList->clear ();
 
+        int i=0;
         for (std::vector<short>::const_iterator it = knownEffects.begin(); it != knownEffects.end(); ++it)
         {
             mAvailableEffectsList->addItem(MWBase::Environment::get().getWorld ()->getStore ().get<ESM::GameSetting>().find(
                                                ESM::MagicEffect::effectIdToString  (*it))->getString());
+            mButtonMapping[i] = *it;
+            ++i;
         }
         mAvailableEffectsList->adjustSize ();
 
@@ -466,7 +469,6 @@ namespace MWGui
             std::string name = MWBase::Environment::get().getWorld ()->getStore ().get<ESM::GameSetting>().find(
                                                ESM::MagicEffect::effectIdToString  (*it))->getString();
             MyGUI::Widget* w = mAvailableEffectsList->getItemWidget(name);
-            w->setUserData(*it);
 
             ToolTips::createMagicEffectToolTip (w, *it);
         }
@@ -518,7 +520,8 @@ namespace MWGui
             return;
         }
 
-        short effectId = *sender->getUserData<short>();
+        int buttonId = *sender->getUserData<int>();
+        short effectId = mButtonMapping[buttonId];
 
         for (std::vector<ESM::ENAMstruct>::const_iterator it = mEffects.begin(); it != mEffects.end(); ++it)
         {

apps/openmw/mwgui/spellcreationdialog.hpp

@@ -88,6 +88,8 @@ namespace MWGui
 
 
     protected:
+        std::map<int, short> mButtonMapping; // maps button ID to effect ID
+
         Widgets::MWList* mAvailableEffectsList;
         MyGUI::ScrollView* mUsedEffectsView;