C#

// Determine the active child form.
          Form activeChild = this.ActiveMdiChild;

          // If there is an active child form, find the active control, which
          // in this example should be a RichTextBox.
          if (activeChild != null)
          {
              try
              {
                  RichTextBox theBox = (RichTextBox)activeChild.ActiveControl;
                  if (theBox != null)
                  {
                      // Put the selected text on the Clipboard.
                      Clipboard.SetDataObject(theBox.SelectedText);

                  }
              }
              catch
              {
                  MessageBox.Show("You need to select a RichTextBox.");
              }

System.IO.StreamReader StreamReader1 = fi.OpenText();             //reads the currently selected text file
String text = StreamReader1.ReadToEnd();
TextEditorForm editForm = new TextEditorForm();                   // creates a new instance of the mdi child form editform
TabPage childTab = new TabPage();                           //create new tab page
editForm.MdiParent = this;                                        //set as child of this form
editForm.Name = "Child" + createdTab.ToString();                  //sets the name of editform to child + 1
editForm.Text = lblFile.Text;                                     //sets the tabpage text to the file name lblfile.text is the file that is currently in the listbox
childTab.Name = editForm.Name;                                    //make sure name and text are same for easier control
childTab.Text = editForm.Text;                                    //this is for syncrhonize later
TextEditortabControl.TabPages.Add(childTab);                      //add new tab
editForm.richTxtBox.Parent = childTab;                            //attach to tab
editForm.richTxtBox.Name = editForm.Name;                         // naming the rtb the same as the rest for easier control
editForm.richTxtBox.ContextMenu = new ContextMenu();              // does not add the contextmenu
ToolStripMenuItem newtexteditMenuTab = new ToolStripMenuItem();   //create menu to hold tab
newtexteditMenuTab.Text = editForm.Text;                          //make sure the name and text are same to synchonize later
newtexteditMenuTab.Name = editForm.Name;                          // still the same name
newtexteditMenuTab.Click += new EventHandler(newMenuTab_Click);   //add event handler
TextEditortabControl.SelectTab(childTab);                         //this is to make sure that tab page is selected in the same time
editForm.EditText = text;                                         //populates the rtb with the selected text file text
editForm.Show();                                                  //as new form created so that corresponding tab and child form is active
createdTab++;                                                     //increment of course
StreamReader1.Close();

public TextEditorForm()
            {  
                this.richTxtBox = new RichTextBox();                
                this.richTxtBox.Dock = DockStyle.Fill;                
                this.richTxtBox.Multiline = true;                
                this.richTxtBox.ScrollBars = RichTextBoxScrollBars.Vertical;
                this.richTxtBox.WordWrap = true;
                this.richTxtBox.DetectUrls = true;
                this.richTxtBox.Visible = true;
                //this.ContextMenu = new ContextMenu(); this didnt work either
               

                
                // Add the RichTextBox to the Form
                this.Controls.Add(this.richTxtBox);

            }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EvenNumberMatrix
{
    class EvenNumbers
    {
        //Exaple of working array
        /*public static int[,] givenArray ={
                                   {5,2,6,8,5,9},
                                   {7,5,3,2,4,7},
                                   {9,6,3,6,4,3},
                                   {8,5,3,6,2,2},
                                   {9,6,3,7,4,7},
                                   {8,5,6,2,2,5}
                               };
         */
        //Not working array
        public static int[,] givenArray ={
                                   {5,2,6,8,5,9},
                                   {7,5,3,2,4,7},
                                   {9,6,3,6,4,2},
                                   {8,5,3,6,2,2},
                                   {9,6,3,7,4,7},
                                   {8,5,6,2,2,5}
                               };
        public static int maxCol = 0, maxRow = 0;
        //temp array to make all odd numbers zeros
        public static int[,] tempGivenArray;
        static void PrintArray(int[,] a)
        {
            for (int x = 0; x < a.GetLength(0); x++)
            {
                for (int y = 0; y < a.GetLength(1); y++)
                {
                    if (a[x, y] != 0)
                    {
                        Console.ForegroundColor = ConsoleColor.Green;
                    }
                    else
                        Console.ForegroundColor = ConsoleColor.Gray;
                    Console.Write(a[x, y] + " ");
                }
                Console.WriteLine();
            }
        }

        static void Main(string[] args)
        {
            int number = 6; int countRows = 0, countCollums = 0, x, y;

            tempGivenArray = new int[number, number];
            // zapisvam 4etnite 4isla v nov masiv samo s nuli
            for (int i = 0; i < number - 1; i++)
            {
                for (int j = 0; j < number - 1; j++)
                {
                    if (givenArray[i, j] % 2 == 0 &&
                        givenArray[i + 1, j] % 2 == 0 &&
                        givenArray[i, j + 1] % 2 == 0 &&
                        givenArray[i + 1, j + 1] % 2 == 0)
                    {
                        tempGivenArray[i, j] = givenArray[i, j];
                        tempGivenArray[i + 1, j] = givenArray[i + 1, j];
                        tempGivenArray[i, j + 1] = givenArray[i, j + 1];
                        tempGivenArray[i + 1, j + 1] = givenArray[i + 1, j + 1];
                    }
                }
            }
            for (int i = 0; i < number - 1; i++)
            {
                for (int j = 0; j < number - 1; j++)
                {
                    x = i; y = j;
                    //loop to check if in a current row even numbers 
                    while (tempGivenArray[x, y] > 0)
                    {
                        x++;
                        countRows++;
                        if (countRows > maxRow)
                            maxRow = countRows;//maxRow holds positions for even number in row
                        if (x > number - 1)//if out of array
                            break;
                    }
                    x = i; y = j; countRows = 0;
                    while (tempGivenArray[x, y] > 0)
                    {
                        y++;
                        countCollums++;
                        if (countCollums > maxCol)//maxCol holds positions for even number in collum
                            maxCol = countCollums;
                        if (y > number - 1)//if out of array 
                            break;
                    }
                    countCollums = 0;

                }
            }
            PrintArray(tempGivenArray);
            Console.WriteLine("The biggest rectangle with even numbers is: "+maxCol * maxRow+" positions!");

        }

    }
}

protected void Page_Init(object sender, EventArgs e)
{
    Page pg = PreviousPage;

    if (pg != null)
    {
        HiddenField hfPrevStudent = Helpers.FindControl<HiddenField>(pg, "hfStudent");
        HiddenField hfPrevSchool = Helpers.FindControl<HiddenField>(pg, "hfSchool");
        if (hfPrevStudent != null)
        {
            hfStudent.Value = hfPrevStudent.Value;
            hfSchool.Value = hfPrevSchool.Value;
        }
    }
}

//I have removed some parts of the method
void SeekWords(string word, int[,] visited, int x, int y)
{
   if (!(x < 0 || x > 4 || y < 0 || y > 4) && visited[x, y] == 0)
   {
      visited[x, y] = 1;
      SeekWords(word + Grid[x, y], visited, x - 1, y - 1);
      SeekWords(word + Grid[x, y], visited, x - 1, y);
      SeekWords(word + Grid[x, y], visited, x - 1, y + 1);
      SeekWords(word + Grid[x, y], visited, x, y - 1);
      SeekWords(word + Grid[x, y], visited, x + 1, y - 1);
      SeekWords(word + Grid[x, y], visited, x + 1, y);
      SeekWords(word + Grid[x, y], visited, x + 1, y + 1);
      visited[x, y] = 0;
   }
}

UserPrincipal getUser = UserPrincipal.FindByIdentity(context, userName);
getUser.Enabled = false;