How to Append data to a combobox

Answer 1

I know this probably doesn't answer your question, but I recommend you close the file connection once you're done using it.

fd = open(files,'rb')
data=fd.readlines()

#Close the connection, you're done using it!
fd.close

#Now do what you want with data.
for i in data[]:
    item=i.strip()
    if item is not None:
       combobox.Append(item)

Answer 2

combobox.SetSelection(0)  # select first item