class EditIntKeyless : public EditInt
{
public:
	EditIntKeyless()
		:convertChecker(this)
	{
		mbutton.AddButton().SetImage(IMG::b_minus).Width(23) <<= callback(this, &EditIntKeyless::OnDec);
		mbutton.AddButton().SetImage(IMG::b_plus) .Width(23) <<= callback(this, &EditIntKeyless::OnInc);
		AddFrame(mbutton);
		SetData(1);
		this->WantFocus(true);
		SetConvert(static_cast<Convert &>(convertChecker));
	}
	void SetupChecker(ChannelChecker *c, int a)
	{
		convertChecker.SetupChecker(c,a);
		convertChecker.Check(GetData());
	}
	virtual void SetData(const Value& data)
	{
		convertChecker.Check(data);
		EditInt::SetData(data);
	}

private:
	void OnInc()   {SetData( 1 + (int) GetData()); WhenAction();}
	void OnDec()   {SetData(-1 + (int) GetData()); WhenAction();}
	MultiButtonFrame mbutton;
	ConvertChecker convertChecker;
};

class ConvertChecker : public ConvertInt
{
public:
	ConvertChecker(EditField *_edit)
		:checker(NULL)
		,addr(-1)
		,channel(-1)
		,edit(_edit)
	{}
	void SetupChecker(ChannelChecker *c, int a) {checker = c; addr = a;}
	
public:
	virtual Value Scan(const Value& text) const
	{
		Value chV = ConvertInt::Scan(text);
		int   ch = chV;
		Check(ch);
		return chV;
	}

	void Check(int64 c) const
	{
		if (channel >= 0)
			UnregisterChannel(channel);
		channel = static_cast<int>(c);

		bool isFree = CheckChannel(channel);
		if (channel >= 0)
			RegisterChannel(channel);
		//edit->Error(!isFree); // <-- this is the source of the problem!
	}

private:
	bool CheckChannel(int ch) const
	{
		if (!checker || addr < 0 || ch < 0)
			return true;
		return checker->IsChannelFree(addr,ch);
	}
	void RegisterChannel(int ch) const
	{
		if (!checker || addr < 0)
			return;
		checker->RegisterChannel(addr,ch);
	}
	void UnregisterChannel(int ch) const
	{
		if (!checker || addr < 0)
			return;
		checker->UnregisterChannel(addr,ch);
	}
	
	ChannelChecker *checker;
	int             addr;
	mutable int     channel;
	EditField      *edit;
};