This idea has been developed and deployed to Canvas
When using the search filter in Canvas Commons, only the "Grade/Level" filter has options to select multiple options at one time and include those results in the search. The "Shared with", "Type", and "Subject" fields only allow you to select one option. It would be helpful for people to be able to select multiple options (check boxes) in these other drop-down fields as well. For example, what if I wanted to search for objects of both images and discussions on a specific species of animal. Currently, using filters, I would have to do two separate searches...or if no filters were applied, then one could use the keyword search...but still would need to use the filters at some point (especially once the object library gets a lot larger).