void UpdateVisibilityBytes()
{
if (_byteProvider == null || _byteProvider.Length == 0)
return;
_startByte = (_scrollVpos + 1) * _iHexMaxHBytes - _iHexMaxHBytes;
_endByte = Math.Min(_byteProvider.Length - 1, _startByte + _iHexMaxBytes);
}
#endregion