title: Plotted arrows aren't displayed below or above bar graph in Pine
body: <p>I have the next code.</p>
  
  <pre><code>//@version=4
  study(title="MACD", shorttitle="MACD")
  
  // Getting inputs
  fast_length = input(title="Fast Length", type=input.integer, defval=11)
  slow_length = input(title="Slow Length", type=input.integer, defval=22)
  src = input(title="Source", type=input.source, defval=close)
  signal_length = input(title="Signal Smoothing", type=input.integer, minval = 1, maxval = 50, defval = 9)
  sma_source = input(title="Simple MA(Oscillator)", type=input.bool, defval=false)
  sma_signal = input(title="Simple MA(Signal Line)", type=input.bool, defval=false)
  
  // Plot colors
  col_grow_above = #26A69A
  col_grow_below = #FFCDD2
  col_fall_above = #B2DFDB
  col_fall_below = #EF5350
  col_macd = #0094ff
  col_signal = #ff6a00
  
  // Calculating
  fast_ma = sma_source ? sma(src, fast_length) : ema(src, fast_length)
  slow_ma = sma_source ? sma(src, slow_length) : ema(src, slow_length)
  macd = fast_ma - slow_ma
  signal = sma_signal ? sma(macd, signal_length) : ema(macd, signal_length)
  hist = macd - signal
  
  plot(hist, title="Histogram", style=plot.style_columns, color=(hist&gt;=0 ? (hist[1] &lt; hist ? col_grow_above : col_fall_above) : (hist[1] &lt; hist ? col_grow_below : col_fall_below) ), transp=0 )
  plot(macd, title="MACD", color=col_macd, transp=0)
  plot(signal, title="Signal", color=col_signal, transp=0)
  
  currMacd = hist[0]
  prevMacd = hist[1]
  
  buy = currMacd &gt; 0 and prevMacd &lt;= 0
  sell = currMacd &lt; 0 and prevMacd &gt;= 0
  
  timetobuy = buy==1
  timetosell = sell==1
  
  tup = barssince(timetobuy[1])
  tdn = barssince(timetosell[1])
  
  long    = tup&gt;tdn?1:na
  short   = tdn&gt;tup?1:na
  
  
  plotshape(long==1?buy:na, color=#26A69A, location=location.abovebar, style=shape.arrowup, title="Buy Arrow", transp=0)
  plotshape(short==1?sell:na, color=#EF5350, location=location.belowbar, style=shape.arrowdown, title="Sell Arrow", transp=0)
  </code></pre>
  
  <p>As you can see, it is the macd histogram code with some plot code to graph arrows near the histogram. I configured their location as above and below. However, they are displayed far from the graph.</p>
  
  <p><a href="https://i.stack.imgur.com/m3Vsz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/m3Vsz.png" alt="macd histogram"></a></p>
  
  <p>How can I plot the arrows above and below the macdh bars? </p>