Steps to reproduce:
1.Open a page with VE
2.Select an image
3.Go to Insert>Gallery
An error appears in the console "Uncaught TypeError: Cannot read property 'body' of undefined"
After that the Media Settings option does not appear on any other image .Also the reference dialog option does not show up when you select a reference note.
Test Environment: http://en.wikipedia.beta.wmflabs.org/
Browser: Chrome Version 26.0.1410.65 & FF 25
OS: MAC OS X 10. 8. 5