Wikimedia Bugzilla is closed!

This problem affects wikiEditor for MW 1.17 - I have not tried other versions.

In jQuery.wikiEditor.toolbar.js, the buildTool function improperly uses a for..in loop to iterate through an array (specifically, for applying filters).  This works fine as long as nobody has added to the Array.prototype, but if they have the for..in loop will pick up non-integer keys.

Although some JavaScript libraries shy away from making changes to prototypes, there are plenty of legacy ones which still do.  

This bug causes blocking JavaScript errors whenever an addition to Array.prototype has a value which causes jQuery to return a wrapped array instead of an actual jQuery collection.