private void startFilterBtn_Click(object sender, EventArgs e)
        {
            skipProxyCheckBtn.Enabled = false;
            cts = new CancellationTokenSource();
            CancellationToken ct = cts.Token;

            List<string> proxyCheckList = new List<string>();

            foreach (var prox in rawProxyList.Items)
            {
                proxyCheckList.Add(prox.ToString());
            }

            int x = 0;
            int y = Convert.ToInt32(totalProxiesLabel.Text);

            // this.ProxyCheckList = proxyCheckList;

            proxyBar.Maximum = proxyCheckList.Count; //this.ProxyCheckList.Count;

            var TaskMain = Task.Factory.StartNew(() =>
            {
                try
                {
                    ct.ThrowIfCancellationRequested();

                    Parallel.ForEach(proxyCheckList,
                        new ParallelOptions { MaxDegreeOfParallelism = Convert.ToInt32(filterThreadCount.Text), CancellationToken = ct }, proxy =>
                        {
                            // check the proxies
                            CheckProxys(proxy, ct);

                            Interlocked.Increment(ref x);
                            Interlocked.Decrement(ref y);

                            // Delegate for accessing controls
                            Invoke(new MethodInvoker(
                                delegate()
                                {
                                    totalProxiesLabel.Text = y.ToString();

                                    rawProxyList.Items.RemoveAt(o);

                                    proxyBar.Value = x;
                                }));
                        });
                }
                // catch cancel exceptions
                catch (OperationCanceledException)
                {
                    Invoke(new MethodInvoker(
                        () =>
                        {
                            skipProxyCheckBtn.Enabled = true;
                            proxyBar.Value = 0;
                        }));
                    return;
                }
                catch (ObjectDisposedException)
                {
                    Invoke(new MethodInvoker(
                        () =>
                        {
                            skipProxyCheckBtn.Enabled = true;
                            proxyBar.Value = 0;
                        }));
                }
                catch (Exception)
                {
                    Invoke(new MethodInvoker(
                        () =>
                        {
                            skipProxyCheckBtn.Enabled = true;
                            proxyBar.Value = 0;
                        }));
                }
            }, ct);
        }