Prevent write to empty vector element

CHANGELOG.md

@@ -278,6 +278,7 @@
     Bug #6276: Deleted groundcover instances are not deleted in game
     Bug #6294: Game crashes with empty pathgrid
     Bug #6606: Quests with multiple IDs cannot always be restarted
+    Bug #6655: Constant effect absorb attribute causes the game to break
     Feature #390: 3rd person look "over the shoulder"
     Feature #832: OpenMW-CS: Handle deleted references
     Feature #1536: Show more information about level on menu

apps/openmw/mwgui/spellcreationdialog.cpp

@@ -109,10 +109,6 @@ namespace MWGui
     {
         bool allowSelf = (effect->mData.mFlags & ESM::MagicEffect::CastSelf) != 0;
         bool allowTouch = (effect->mData.mFlags & ESM::MagicEffect::CastTouch) && !mConstantEffect;
-        bool allowTarget = (effect->mData.mFlags & ESM::MagicEffect::CastTarget) && !mConstantEffect;
-
-        if (!allowSelf && !allowTouch && !allowTarget)
-            return; // TODO: Show an error message popup?
 
         setMagicEffect(effect);
         mEditing = false;
@@ -617,6 +613,13 @@ namespace MWGui
         const ESM::MagicEffect* effect =
             MWBase::Environment::get().getWorld()->getStore().get<ESM::MagicEffect>().find(mSelectedKnownEffectId);
 
+        bool allowSelf = (effect->mData.mFlags & ESM::MagicEffect::CastSelf) != 0;
+        bool allowTouch = (effect->mData.mFlags & ESM::MagicEffect::CastTouch) && !mConstantEffect;
+        bool allowTarget = (effect->mData.mFlags & ESM::MagicEffect::CastTarget) && !mConstantEffect;
+
+        if (!allowSelf && !allowTouch && !allowTarget)
+            return; // TODO: Show an error message popup?
+
         if (effect->mData.mFlags & ESM::MagicEffect::TargetSkill)
         {
             delete mSelectSkillDialog;