Guard against IOOBEs when rendering the new spell trade icon, fixes #565

src/main/java/electroblob/wizardry/client/gui/WizardTradeTweaksHandler.java

@@ -90,6 +90,8 @@ public class WizardTradeTweaksHandler {
 			// New spell indicator
 			if(gui.inventorySlots instanceof ContainerMerchant){
 
+				if(tradeIndex < trades.size()){ // Seems to happen with certain mods' GUIs
+
 					// Can't use getCurrentRecipe because that only gets updated when the correct items are given
 					MerchantRecipe recipe = trades.get(tradeIndex);
 
@@ -125,5 +127,6 @@ public class WizardTradeTweaksHandler {
 				}
 			}
 		}
+	}
 
 }