combopopup overlapping inputfield

run the example and follow this sequence to reproduce the problem:

1) focus into the combobox
2) type "ge"
-> all the german locales appear in the popup (opening above the input field)
3) hit backspace until only the letter "g" remains in the input field
-> languages like greek are added to the possible choices (expected)
-> the combopopup overlaps the input field hiding further input