custom element Anchors capture object picking

[AttilaVM]

I ran into an esoteric bug:

Custom element anchors were picked by pick_object(x, y) from the scene module using version 16.12.1. on GNU/Linux (which I guess is not relevant)

This bug was also experienced by at least one other person, see this post

I made a self-contained example:

example

To reproduce just unzip the archive in your b4w project directory. Open the anchor_bug.html from the project manager. Click to different points on the anchor fixed black divs (I disabled the pointer events on them), and on certain mouse positions the anchors will be picked instead of the cubes, you will see it in the js console. Of course the error also occurs when you click next to a div.

I found the cause and made a dirty fix or workaround, however I did not spend enough time on it, so it is possible that this change will disable some other functionality:

@@ -1749,11 +1749,6 @@ exports.pick_object = function(canvas_x, canvas_y) {
         return null;
     }
 
-    var anchor = m_anchors.pick_anchor(canvas_x, canvas_y);
-
-    if (anchor)
-        return anchor;
-
     var color = m_scenes.pick_color(main_scene, canvas_x, canvas_y);
 
     if (!color)

My suggestion is that anchor picking code should be separated from the pick_object function to its own function to avoid confusions like this.