TextBox with Placeholder

Potential fix:
Add on PlaceholderTextBox the following properties:
They will hide the inherited ones with same names.

#region PasswordChar
char _passwordChar;
[Browsable(true)]
[DefaultValue('\0')]
public char PasswordChar
{
	get { return _passwordChar; }
	set
	{
		_passwordChar = value;
		if (!IsPlaceholderActive)
			base.PasswordChar = value;
	}
}
#endregion

#region UseSystemPasswordChar
bool _useSystemPasswordChar;
[Browsable(true)]
public bool UseSystemPasswordChar
{
	get { return _useSystemPasswordChar; }
	set
	{
		_useSystemPasswordChar = value;
		if (!IsPlaceholderActive)
			base.UseSystemPasswordChar = value;
	}
}
#endregion

Add the following code at the beginning of the OnPlaceholderActiveChanged method:

if (newValue)
{
	base.UseSystemPasswordChar = (Boolean)((DefaultValueAttribute)typeof(TextBox).GetProperty("UseSystemPasswordChar").GetCustomAttributes(typeof(DefaultValueAttribute), false)[0]).Value;
	base.PasswordChar = (Char)((DefaultValueAttribute)typeof(TextBox).GetProperty("PasswordChar").GetCustomAttributes(typeof(DefaultValueAttribute), false)[0]).Value;
}
else
{
	base.PasswordChar = this.PasswordChar;
	base.UseSystemPasswordChar = this.UseSystemPasswordChar;
}

protected override void OnKeyDown(KeyEventArgs e)
{
    // Prevents the user from going through the placeholder with arrow keys and placeholder is not deletable with delete or backspace key
    if (IsPlaceholderActive && (e.KeyCode == Keys.Left || e.KeyCode == Keys.Right || e.KeyCode == Keys.Up ||
                                e.KeyCode == Keys.Down || e.KeyCode == Keys.Delete || e.KeyCode == Keys.Back ||
                                e.KeyCode == Keys.Home || e.KeyCode == Keys.End))
    {
        e.SuppressKeyPress = true;
    }

    // This fires, but does not work... not sure why yet!!
    if (IsPlaceholderActive && e.KeyCode == Keys.A && e.Modifiers.HasFlag(Keys.Control))
    {
        e.SuppressKeyPress = true;
    }

    base.OnKeyDown(e);
}

protected override void OnKeyDown(KeyEventArgs e)
{

    // Prevents the user from going through the placeholder with arrow keys and placeholder is not deletable with delete or backspace key
    if (IsPlaceholderActive && (e.KeyCode == Keys.Left || e.KeyCode == Keys.Right || e.KeyCode == Keys.Up ||
                                e.KeyCode == Keys.Down || e.KeyCode == Keys.Delete || e.KeyCode == Keys.Back ||
                                e.KeyCode == Keys.Home || e.KeyCode == Keys.End))
    {
        e.SuppressKeyPress = true;
    }

    if (IsPlaceholderActive && e.KeyCode == Keys.A && e.Modifiers.HasFlag(Keys.Control))
    {
        e.SuppressKeyPress = true;
        DeselectAll();
    }
    base.OnKeyDown(e);
}

private ContextMenuStrip _contextMenuStrip;

private void InitialiseContextMenu()
{
    var menuItems = new List<ToolStripItem>();
    var cutMenuItem = new ToolStripMenuItem("Cu&t");
    cutMenuItem.Click += CutMenuItemClick;
    menuItems.Add(cutMenuItem);

    var copyMenuItem = new ToolStripMenuItem("&Copy");
    copyMenuItem.Click += CopyMenuItemClick; ;
    menuItems.Add(copyMenuItem);

    var pasteMenuItem = new ToolStripMenuItem("&Paste");
    pasteMenuItem.Click += PasteMenuItemClick;
    menuItems.Add(pasteMenuItem);

    var selectAllMenuItem = new ToolStripMenuItem("Select &All");
    selectAllMenuItem.Click += SelectAllMenuItemClick; ;
    menuItems.Add(selectAllMenuItem);

    _contextMenuStrip = new ContextMenuStrip();
    _contextMenuStrip.Items.AddRange(menuItems.ToArray());
    ContextMenuStrip = _contextMenuStrip;
    ContextMenuStrip.Opening += ContextMenuStripOpening;
}

private void ContextMenuStripOpening(object sender, CancelEventArgs e)
{
    _contextMenuStrip.Items[0].Enabled = SelectionLength > 0;
    _contextMenuStrip.Items[1].Enabled = SelectionLength > 0;
    _contextMenuStrip.Items[2].Enabled = Clipboard.ContainsText();
    _contextMenuStrip.Items[3].Enabled = TextLength > 0;
}

private void CopyMenuItemClick(object sender, EventArgs e)
{
    Copy();
}

private void CutMenuItemClick(object sender, EventArgs e)
{
    Cut(); ;
}

private void PasteMenuItemClick(object sender, EventArgs e)
{
    Paste();
}

private void SelectAllMenuItemClick(object sender, EventArgs e)
{
    SelectAll();
}

/// <summary>
///     Initializes a new instance of the PlaceholderTextBox class.
/// </summary>
public PlaceholderTextBox()
{
    // Through this line the default placeholder gets displayed in designer
    base.Text = PlaceholderText;
    TextColor = SystemColors.WindowText;
    PlaceholderTextColor = SystemColors.InactiveCaption;
    InitialiseContextMenu();
    SetStyle(ControlStyles.UserMouse, true);
}

public override int TextLength => IsPlaceholderActive ? 0 : base.TextLength;