I want to make RichTextBox very similar to Windows Command Prompt (cmd.exe).
It means that I need that nobody can delete the prompt and move cursor in
window except in the same line.
I use the following code:

if (e->KeyCode == Keys::Enter && connection == NULL ){
       NetPromptBox->SelectAll();
       NetPromptBox->SelectionProtected = false;
       NetPromptBox->Text =
String::Concat(NetPromptBox->Text,S"\r\nSERVER>> ");
       NetPromptBox->SelectAll();
       NetPromptBox->SelectionProtected = true;
       NetPromptBox->SelectionLength = 0;
       NetPromptBox->SelectionStart = NetPromptBox->TextLength+1;
}

The problem is that user can still go up and down in window and the cursor
after you press ENTER is not in the same line as SERVER>> but in next one.

Could anybody help me please?

Thank you,
Przemyslaw Lopaciuk