mql4 envelope EA opens two trades on same bar? - mql4

Question

my strategy is based on the envelope indicator :
-for a buy order a candle has to close above the envelope line
-for a sell order the candle has to close below the envelope line
The EA seems to enter trades based on those rules but whenever a candle closes above the envelope line and the EA enters a buy trade if the sl has been it immediately opens another trade without checking the rules for a buy or sell order
//+------------------------------------------------------------------+
//| ProjectName |
//| Copyright 2018, CompanyName |
//| http://www.companyname.net |
//+------------------------------------------------------------------+
input double StopLoss=50.0; // Stop Loss in pips
input double TakeProfit=100.0; // Take Profit in pips
//+------------------------------------------------------------------+
//| |
//+------------------------------------------------------------------+
void OnTick()
{
//create an empty string for the signal
string signal="";
//symbol, period,14 candles,SMA,no shift,close price,deviation 0.10,buffer line,candle 0
double LowerBand=iEnvelopes(_Symbol,_Period,14,MODE_SMA,0,PRICE_CLOSE,0.10,MODE_LOWER,0);
double UpperBand=iEnvelopes(_Symbol,_Period,14,MODE_SMA,0,PRICE_CLOSE,0.10,MODE_UPPER,0);
//if close price is below lower band
if(Close[1]<LowerBand)
{
signal="sell";
}
//if close price is above upper band
if(Close[1]>UpperBand)
{
signal="buy";
}
if(signal=="sell"&&OrdersTotal()==0)
{
//send a sell order
double sellSL=Bid+StopLoss*_Point;
double sellTP=Bid-TakeProfit*_Point;
OrderSend(_Symbol,OP_SELL,0.10,Bid,3,sellSL,sellTP,NULL,0,0,Red);
}
if(signal=="buy"&&OrdersTotal()==0)
{
//send a buy order
double buySL=Ask-StopLoss*_Point;
double buyTP=Ask+TakeProfit*_Point;
OrderSend(_Symbol,OP_BUY,0.10,Ask,3,buySL,buyTP,NULL,0,0,Green);
}
// create a chart output
Comment("BLZ TRADING EA");
}
//+------------------------------------------------------------------+