DrawText does not persist on past bars

[tjw0001]

I am trying to print a letter above each bar. Within 'OnBarUpdate()' I am using:

DrawText("wavetag", waveDir[0], 0, High[0]+TickSize, Color.Black);

The letter I want to print displays fine on the current bar, but as each bar updates the letter disappears from past bars. I want it to stay, so each bar has a letter over it. How do I make the text persistent for each bar?

[NinjaTrader_ChelseaB]

Hello tjw0001,

When you reuse a tag name for a drawing object it causes the object to overwrite the previous object.

If you use a unique tag name it will not overwrite the object.

Try:
DrawText("wavetag"+CurrentBar, waveDir[0], 0, High[0]+TickSize, Color.Black);