The solution for bash-4 is to remove the colon from COMP_WORDBREAKS:
COMP_WORDBREAKS=${COMP_WORDBREAKS//:}
The workaround for bash-3, or bash-4 with a colon in COMP_WORDBREAKS,
is to call:
__ltrim_colon_completions "$cur"
after completions have been put in COMPREPLY.
See also: E13) Why does filename completion misbehave if a colon appears
in the filename? - Bash FAQ, http://tiswww.case.edu/php/chet/bash/FAQ
