Merge pull request #236 from fidelthomet/patch-1

Docs: Update default value for zoom.filter

README.md

@@ -162,7 +162,7 @@ If *filter* is specified, sets the filter to the specified function and returns
 
 ```js
 function filter(event) {
-  return !event.ctrlKey && !event.button;
+  return (!event.ctrlKey || event.type === 'wheel') && !event.button;
 }
 ```