Blank Lines in HTML Filtering Settings "Custom attributes" Breaks TinyMCE

[flipmcf]

It's a pretty cool way to ruin someone's plone installation!
go to @@filter-controlpanel and add two blank lines to "Custom Attributes" and watch mosaic and tinyMCE break.

specifically for the mosaic editor, you get Failed while initializing 'layout' pattern. TypeError: i[2] is undefined in your javascript console.

The effect is deep inside TinyMCE javascript where there aren't any matches to a regexp, yet the javascript still tries to access and use 'matches[2]' and gets an Type Error: undefined. The javascript should be fixed, it's where the edge case should be handled, but it's easier just to fix it in Plone I would imagine.

Simply filtering out empty strings should fix this simple issue.