Check if not a left-click, then bail out of onStart

Author: Alex Vinober

src/components/dragelement/index.js

@@ -78,6 +78,10 @@ dragElement.init = function init(options) {
     element.ontouchstart = onStart;
 
     function onStart(e) {
+        if(e.button && e.button === 2) {    // right click
+            return;
+        }
+
         // make dragging and dragged into properties of gd
         // so that others can look at and modify them
         gd._dragged = false;