List BackgroundColor?

When I select some paras and create them into the list.
(before creating the list,I don't set backgroundcolor deliberately)

After creating the list,Now I want to set the backgroundcolor of one listitem,

when setting,I will get an error

TypeError: Error #1034: Type Coercion failed: cannot convert flash.display::Shape@8a11331 to flash.text.engine.TextLine.

then, I click DismissAll button,now I remove the list into the paras, but the listitem that I selected just now has a backgroundcolor

Is it a bug or ...?

//Note

1. if it is list ,I can only set color ,but can't set backgroundcolor

2. if it isn't list , I can set color and backgroundcolor

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P1. select some paras and create them into the list,now click backgroundColor button to set backgroundColor ,I get the error;

Pic2. I click dismissAll btn,then I remove the list, what can you see? The para that changed from the listitem  has been set the backgroudcolor!!!!!!!!!!!!!!!!!!!!