Calendar should disappear when its container no more in focus

STEPS:
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1/ Go create a new namespace ('work', 'http://www.work.net/0.1').
2/ Edit the basedocument, notice it has three Date fields: Creation, Modification, Publication and corresponding three Calendars.
3/ Click on one of the Calendars, then on another and see that the previous one is still open.
4/ I don't think this is the intended behavior, and I expect the previous calendar to be closed when I clicked the mouse on another widget (thus making it active).

Note: alternative to 2/ is to click on one Calendar, then click on any other widget on that same document type, one without a Calendar. The previously open Calendar should be closed when t he other widget gets in focus.