updated for version 7.4.559 Problem: Appending a block in the middle of a tab does not work correctly when virtualedit is set. Solution: Decrement spaces and count, don't reset them. (James McCoy)

start:
test for empty string: ok
test for 1 char: ok
test for 3 chars: ok
test for contains meta char: ok
test for contains non-ascii char: ok