is there any way to have 'click event' for combobox in commandbar?

[how_fly]

i have added a new combobox in a new commandbar in Word.
i have 2 questions:

1. is there any way to have 'click event' for the combobox? so when user
input 'enter', combobox can capture the input character and have some
response.

2. i find, when user inputs a stirng in the combobox, then clicks other
toolbar, this new input-string disappears, and the combobox has returned to
blank in its editctrl. why? how can the combobox save the new input-stirng ?

thanks alot for any help

 

[how_fly]

ps:
this is for word2003.