I am using a value aware combobox, it was working fine, but recently i started getting the below error, when I try to click on combobox, and the error is random. I am not sure of it is because of any changes i have done in the coding, or some changes in data provider etc any help is appreciated... TypeError: Error #1009: Cannot access a property or method of a null object reference. at mx.controls::ComboBox/destroyDropdown() at mx.controls::ComboBox/styleChanged() at mx.core::UIComponent/setBorderColorForErrorString() at mx.core::UIComponent/commitProperties() at mx.controls::ComboBase/commitProperties() at mx.controls::ComboBox/commitProperties() at custom.controls::ComboBox/commitProperties()[D:\workspace\eclipse\indigo\ams\flex_src\custom\controls\ComboBox.mxml:13] at mx.core::UIComponent/validateProperties() at mx.managers::LayoutManager/validateProperties() at mx.managers::LayoutManager/doPhasedInstantiation() Debugger throws TypeError: Error #1009: Cannot access a property or method of a null object reference. at mx.controls::ComboBox/destroyDropdown() at mx.controls::ComboBox/styleChanged() at mx.core::UIComponent/setBorderColorForErrorString() at mx.core::UIComponent/commitProperties() at mx.controls::ComboBase/commitProperties() at mx.controls::ComboBox/commitProperties() at custom.controls::ComboBox/commitProperties()[D:\workspace\eclipse\indigo\ams\flex_src\custom\controls\ComboBox.mxml:13] at mx.core::UIComponent/validateProperties() at mx.managers::LayoutManager/validateProperties() at mx.managers::LayoutManager/doPhasedInstantiation() at mx.managers::LayoutManager/validateNow() at mx.controls::ComboBox/displayDropdown() at mx.controls::ComboBox/downArrowButton_buttonDownHandler() at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent() at mx.controls::Button/http://www.adobe.com/2006/flex/mx/internal::buttonPressed() at mx.controls::Button/mouseDownHandler() at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.core::UIComponent/dispatchEvent() at mx.controls::ComboBase/textInput_mouseEventHandler()