add comment regarding new selection plotly_selected points

Author: archmoj

src/components/selections/select.js

@@ -377,6 +377,8 @@ function prepSelect(evt, startX, startY, dragOptions, mode) {
         throttle.done(throttleID).then(function() {
             throttle.clear(throttleID);
 
+            // Only points selected by the new selection are presented in eventData here
+            // Should we provide all the selected points instead?
             dragOptions.gd.emit('plotly_selected', eventData);
 
             if(!immediateSelect && currentPolygon && dragOptions.selectionDefs) {