As an alternative to the above or while picking out element from Dynamic components or lists which are generated on the fly. Pick out the parent element rather than a specific child element. This can be easily done by picking the child element and expanding the selection.
The chances of the above balloon pointing to the correct column is highly unlikely as the layout may differ from user to user. Instead, it would be a good practice to select the entire header and position to the center for a consistent balloon positioning.