Code overwrite.

After the loading workspace, the changed block code becomes the code, when the block was created. I create block in GUI and remake the part of code.
Default

import net.minecraftforge.fml.relauncher.SideOnly;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.common.registry.GameRegistry;
import net.minecraftforge.fml.common.event.FMLServerStartingEvent;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;

import net.minecraft.world.gen.feature.WorldGenMinable;
import net.minecraft.world.World;
import net.minecraft.world.IBlockAccess;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.AxisAlignedBB;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.BlockRenderLayer;
import net.minecraft.item.ItemStack;
import net.minecraft.item.Item;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.client.renderer.block.model.ModelResourceLocation;
import net.minecraft.client.Minecraft;
import net.minecraft.block.state.IBlockState;
import net.minecraft.block.material.Material;
import net.minecraft.block.SoundType;
import net.minecraft.block.Block;

import java.util.Random;

public class mcreator_cobaltShardOre {

    public mcreator_cobaltShardOre() {
    }

    public static BlockCobaltShardOre block;

    public static Object instance;

    public int addFuel(ItemStack fuel) {
        return 0;
    }

    public void serverLoad(FMLServerStartingEvent event) {
    }

    public void preInit(FMLPreInitializationEvent event) {
    }

    public void registerRenderers() {
    }

    public void load(FMLInitializationEvent event) {
        if (event.getSide() == Side.CLIENT) {
            Minecraft.getMinecraft().getRenderItem().getItemModelMesher()
                    .register(Item.getItemFromBlock(block), 0, new ModelResourceLocation("TestEnvironmentMod:CobaltShardOre", "inventory"));
        }
    }

    static {

        block = (BlockCobaltShardOre) (new BlockCobaltShardOre().setHardness(8.0F).setResistance(25.0F).setLightLevel(0.0F)
                .setUnlocalizedName("CobaltShardOre").setLightOpacity(0).setCreativeTab(CreativeTabs.BUILDING_BLOCKS));
        block.setHarvestLevel("pickaxe", 4);
    }

    public void generateSurface(World world, java.util.Random rand, int chunkX, int chunkZ) {
        for (int i = 0; i < 10; i++) {
            int randPosX = chunkX + rand.nextInt(16);
            int randPosY = rand.nextInt(113) + 15;
            int randPosZ = chunkZ + rand.nextInt(16);
            (new WorldGenMinable(mcreator_cobaltShardOre.block.getDefaultState(), 16)).generate(world, rand, new BlockPos(randPosX, randPosY,
                    randPosZ));
        }
    }

    public void generateNether(World world, Random random, int chunkX, int chunkZ) {
    }

    static class BlockCobaltShardOre extends Block {

        int a1 = 0, a2 = 0, a3 = 0, a4 = 0, a5 = 0, a6 = 0;

        boolean red = false;

        protected BlockCobaltShardOre() {
            super(Material.IRON);

            GameRegistry.registerBlock(this, "CobaltShardOre");
            setSoundType(SoundType.STONE);

        }

        @Override
        public void onBlockAdded(World world, BlockPos pos, IBlockState state) {
            int i = pos.getX();
            int j = pos.getY();
            int k = pos.getZ();
            EntityPlayer entity = Minecraft.getMinecraft().thePlayer;
            world.scheduleUpdate(new BlockPos(i, j, k), this, this.tickRate(world));

        }

        @Override
        public int getWeakPower(IBlockState blockState, IBlockAccess blockAccess, BlockPos pos, EnumFacing side) {
            return red ? 15 : 0;
        }

        @Override
        public int getStrongPower(IBlockState blockState, IBlockAccess blockAccess, BlockPos pos, EnumFacing side) {
            return red ? 15 : 0;
        }

        @SideOnly(Side.CLIENT)
        @Override
        public BlockRenderLayer getBlockLayer() {
            return BlockRenderLayer.SOLID;
        }

        @Override
        public AxisAlignedBB getBoundingBox(IBlockState state, IBlockAccess source, BlockPos pos) {
            return new AxisAlignedBB(0.0D, 0.0D, 0.0D, 1.0D, 1.0D, 1.0D);
        }

        @Override
        public int tickRate(World world) {
            return 10;
        }

        @Override
        public int quantityDropped(Random par1Random) {
            return 1;
        }

        @Override
        public Item getItemDropped(IBlockState state, Random par2Random, int par3) {
            return new ItemStack(mcreator_cobaltShard.block).getItem();
        }
    }
}

Need

import net.minecraftforge.fml.relauncher.SideOnly;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.common.registry.GameRegistry;
import net.minecraftforge.fml.common.event.FMLServerStartingEvent;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;

import net.minecraft.world.gen.feature.WorldGenMinable;
import net.minecraft.world.World;
import net.minecraft.world.IBlockAccess;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.AxisAlignedBB;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.BlockRenderLayer;
import net.minecraft.item.ItemStack;
import net.minecraft.item.Item;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.client.renderer.block.model.ModelResourceLocation;
import net.minecraft.client.Minecraft;
import net.minecraft.block.state.IBlockState;
import net.minecraft.block.material.Material;
import net.minecraft.block.SoundType;
import net.minecraft.block.Block;

import java.util.Random;

public class mcreator_cobaltShardOre {

    public mcreator_cobaltShardOre() {
    }

    public static BlockCobaltShardOre block;

    public static Object instance;

    public int addFuel(ItemStack fuel) {
        return 0;
    }

    public void serverLoad(FMLServerStartingEvent event) {
    }

    public void preInit(FMLPreInitializationEvent event) {
    }

    public void registerRenderers() {
    }

    public void load(FMLInitializationEvent event) {
        if (event.getSide() == Side.CLIENT) {
            Minecraft.getMinecraft().getRenderItem().getItemModelMesher()
                    .register(Item.getItemFromBlock(block), 0, new ModelResourceLocation("TestEnvironmentMod:CobaltShardOre", "inventory"));
        }
    }

    static {

        block = (BlockCobaltShardOre) (new BlockCobaltShardOre().setHardness(8.0F).setResistance(25.0F).setLightLevel(0.0F)
                .setUnlocalizedName("CobaltShardOre").setLightOpacity(0).setCreativeTab(CreativeTabs.BUILDING_BLOCKS));
        block.setHarvestLevel("pickaxe", 4);
    }

    public void generateSurface(World world, java.util.Random rand, int chunkX, int chunkZ) {
        for (int i = 0; i < 6; i++) {
            int randPosX = chunkX + rand.nextInt(16);
            int randPosY = rand.nextInt(36) + 15;
            int randPosZ = chunkZ + rand.nextInt(16);
            (new WorldGenMinable(mcreator_cobaltShardOre.block.getDefaultState(), 3)).generate(world, rand, new BlockPos(randPosX, randPosY,
                    randPosZ));
        }
    }

    public void generateNether(World world, Random random, int chunkX, int chunkZ) {
    }

    static class BlockCobaltShardOre extends Block {

        int a1 = 0, a2 = 0, a3 = 0, a4 = 0, a5 = 0, a6 = 0;

        boolean red = false;

        protected BlockCobaltShardOre() {
            super(Material.IRON);

            GameRegistry.registerBlock(this, "CobaltShardOre");
            setSoundType(SoundType.STONE);

        }

        @Override
        public void onBlockAdded(World world, BlockPos pos, IBlockState state) {
            int i = pos.getX();
            int j = pos.getY();
            int k = pos.getZ();
            EntityPlayer entity = Minecraft.getMinecraft().thePlayer;
            world.scheduleUpdate(new BlockPos(i, j, k), this, this.tickRate(world));

        }

        @Override
        public int getWeakPower(IBlockState blockState, IBlockAccess blockAccess, BlockPos pos, EnumFacing side) {
            return red ? 15 : 0;
        }

        @Override
        public int getStrongPower(IBlockState blockState, IBlockAccess blockAccess, BlockPos pos, EnumFacing side) {
            return red ? 15 : 0;
        }

        @SideOnly(Side.CLIENT)
        @Override
        public BlockRenderLayer getBlockLayer() {
            return BlockRenderLayer.SOLID;
        }

        @Override
        public AxisAlignedBB getBoundingBox(IBlockState state, IBlockAccess source, BlockPos pos) {
            return new AxisAlignedBB(0.0D, 0.0D, 0.0D, 1.0D, 1.0D, 1.0D);
        }

        @Override
        public int tickRate(World world) {
            return 10;
        }

        @Override
        public int quantityDropped(Random par1Random) {
               return 1 +(int)(Math.random()*3);
        }

        @Override
        public Item getItemDropped(IBlockState state, Random par2Random, int par3) {
            return new ItemStack(mcreator_cobaltShard.block).getItem();
        }
    }
}

How to change the code, that it has not changed later?