Hi Sweety,
Greetings from Syncfusion, we have analyzed your requirement to place the tooltip in a desired position as your current tooltip is rendered at the bottom in a column series, and regarding this, we like to explain the behavior of our tooltip in detail. Our tooltip will arrange smartly based on the position of the data, by default a tooltip will always appear at the top of the data point, but in some case let us say for e.g. your y-axis maximum range is 50 and your data point is 49, then the tooltip will not have enough space to showcase it at the top of the data point and thus it changes the position to bottom smartly to show the full tooltip.
But in your case, you are using a tooltip template with stack layout and listview bound to a collection and thus the stack layout size increases and there is no space to show case the tooltip at top by default and it moves to the bottom and both cases due to long list there is no space to view the tooltip fully.
So, we recommend you to use ViewAnnotation and SelectionChanged event in chart to achieve your requirement to show a list on clicking a data point instead of tooltip template. The ViewAnnotation can be placed anywhere inside the chart using SelectionChagned event.
You can learn more on ViewAnnotation and SelectionChagned event from the below user guide documents
UG links:
We are currently preparing a sample based on this and we will update you the sample by tomorrow September 19th 2018, we appreciate your patience until then.
Thanks,
Michael