history-graph: tap_action only works for a POINT, not for a LINE

[ildar170975]

Some time ago a tap_action was added to history-graph.
#18036
For linear graphs it only works for points - not for lines between points.
Consider a simple graph for a value "1 -> 0 -> 1":

Tapping only on these points will show more-info:

Or even for a simple graph - only these 2 points:

I wonder is it possible to provide a tap-action for a whole curve?