Cortana will not stay on for questions on pc?

[WPCentral Question]

Cortana will not come on unless I push the mic button on pc for every question. I have her turned on in the setting. What else do I need to do? I have Cortana on my pc. I have to turn on the mic for every question. If I say hello Cortana she will answer hello them to ask my question I have to push the mic button again to ask the question. Is this right or is there a setting that I have missed?