Behind the scene, the filter for each column is then combined to filter the entire the table. Within each filter, the values are "OR'ed", while among filters, the values are "AND'ed". For example, the combined filter to the left means | Panel |
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"Show me all study requests that have modalities of either Magnetic Resonance OR Computed Tomography. AND, in addition, show me only the requests that have been requested in the time period of 7/13/2011 14:01:40-07/15/2011 10:32:45." |
Users do not have to do anything to combine filters explicitly. The filters are always active. As soon as users click on a checkbox, or release an endpoint in the range slider, a new | 
