You can display flags on the chart to indicate a trade took place. In the preferences panel, check the appropriate check box, choose the color of the popup panel and the size of the pin.

Screen Shot 2013-11-28 at 9.58.44 PM

When you place the mouse on the flag, a panel popups with information about the trade.

Screen Shot 2013-11-28 at 9.58.29 PM

You can decide to, either mark the exact value, or position the flag above the high of the day not to interfere with the chart.