How to assign a key word to multiple images

I used to be able to assign a keyword to multiple images simultaneously.

Now Aperature only allows me to assign a keyword one image at a time.

I seem to inadvertently turned off the ability to assign key words to groups of images. Happens with star ratings also.

Does anyone know which menu command I can turn this one image at a time setting and go back to assigning to multiple selected images?

Thanks

Mark