# Strange error ComboBox component

**URL:** <https://forum.kirupa.com/t/strange-error-combobox-component/282532>\
**Category:** flash\
**Created:** [February 23, 2009, 1:12pm UTC](https://forum.kirupa.com/t/strange-error-combobox-component/282532 "2009-02-23T13:12:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![codetale](https://avatars.discourse-cdn.com/v4/letter/c/7ea924/32.png) [@codetale](https://forum.kirupa.com/u/codetale)\
**Post date:** [February 23, 2009, 1:12pm UTC](https://forum.kirupa.com/t/strange-error-combobox-component/282532/1 "2009-02-23T13:12:29Z")

</div>

i use fl.control.ComboBox

mycombobox.visible = false;

and it throw me a strange error,

> TypeError: Error #1034: Type Coercion failed: cannot convert fl.events::ComponentEvent@1b469d81 to CustomEvents.CosEvent.  
> at flash.events::EventDispatcher/flash.events:EventDispatcher::dispatchEventFunction()  
> at flash.events::EventDispatcher/dispatchEvent()  
> at fl.core::UIComponent/set visible()

the “CustomEvents.CosEvent” is my custom event that extend Event,  
but however, the combobox i have no assign any addEventListener to it, and howcome it dispatch my custom event?

any know what happen?

thank you very much