Some of my users QwtPlotMultiBarCharts are very complicated and it's not always easy to determine the legend title for each small section of each bar. They would like to be able to hover over a bar section and have the program show the legend title as a tool tip. If the performance is too slow, I can change the implementation to having the user click first and then display the text.

I'm overloading QwtPlotPicker::trackerTextF() trying to display the legend title of the bar section that is under the cursor.

I've successfully overloaded the trackerTextF() so that my method is being called rather than the QwtPlotPicker version.
I've successfully accessed the QwtPlotMultiBarChart::legendData & I see all my legend titles.

My problem is determining what section of the bar is under the cursor. I thought at first I could loop through the series data and find what is under the cursor based on the x and y coordinates but this doesn't work since sometimes the multi bars are stacked and sometimes they are grouped. Is there a way to ask qwt what is under the cursor? What am I missing?

Any help in accomplishing this task would be greatly appreciated.