Sometimes my classes have many methods, those methods filled the entire combobox, and i need use the arrows to scroll, or my mouse wheel. The sugestion is when i press a letter in my keyboard, the combobox set the position of the first method with the letter that i've pressed. Ex: If a press "R", the combobox set the position to "ReadFiles".
I think this is not possible in wx2.8.10, or if possible would not be working very well.
Wx3.0.0 will have a way to implement auto-completion in edit/combo boxes.