Requested from: http://forums.bukkit.org/threads/anti-shift-clicking-armor.124529/

AntiShiftClicker.java

package com.gmail.mooman219;

import java.util.logging.Logger;

import org.bukkit.Material;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.java.JavaPlugin;

public class AntiShiftClicker extends JavaPlugin implements Listener {
    private static final Logger log = Logger.getLogger("Minecraft");

    @Override
    public void onEnable() {
        this.getServer().getPluginManager().registerEvents(this, this);

        PluginDescriptionFile pdfFile = getDescription();
        log.info(pdfFile.getName() + " v" + pdfFile.getVersion() + " enabled. Created by: " + pdfFile.getAuthors());
    }

    @Override
    public void onDisable() {
        PluginDescriptionFile pdfFile = getDescription();
        log.info(pdfFile.getName() + " v" + pdfFile.getVersion() + " disabled. Created by: " + pdfFile.getAuthors());
    }

    @EventHandler()
    public void onClick(InventoryClickEvent event) {
        if(event.isShiftClick()) {
            event.setCancelled(true);
        }
    }

    @SuppressWarnings("deprecation")
    @EventHandler()
    public void onInteract(PlayerInteractEvent event) {
        if(event.hasItem() && event.getItem() != null && isArmor(event.getItem().getType())) {
            event.setCancelled(true);
            event.getPlayer().updateInventory();
        }
    }

    public boolean isArmor(Material material) {
        switch(material) {
        case GOLD_HELMET:
        case DIAMOND_HELMET:
        case IRON_HELMET:
        case CHAINMAIL_HELMET:
        case LEATHER_HELMET:
        case GOLD_CHESTPLATE:
        case DIAMOND_CHESTPLATE:
        case IRON_CHESTPLATE:
        case CHAINMAIL_CHESTPLATE:
        case LEATHER_CHESTPLATE:
        case GOLD_LEGGINGS:
        case DIAMOND_LEGGINGS:
        case IRON_LEGGINGS:
        case CHAINMAIL_LEGGINGS:
        case LEATHER_LEGGINGS:
        case GOLD_BOOTS:
        case DIAMOND_BOOTS:
        case IRON_BOOTS:
        case CHAINMAIL_BOOTS:
        case LEATHER_BOOTS:
            return true;
        default:
            return false;
        }
    }
}