为什么日期选择器会意外触发JComboBox的actionPerformed？

I have two date picker components and a JComboBox component with their associated Action Listeners. My problem is this: When I select a date from any of the date pickers, not their associated events are fired but also the event for JComboBox is fired. To add to the surprise, the event for JComboBox is fired first! I have two date picker components and a JComboB