Partial removal of captured groups when replacing

It happens when searching a regexp with a capture group and replacing them without references of the capture group globally (Replace All). The matches of first capture group is incorrectly inserted.

Tested with mousepad 0.6.5.

Example:

Test document:

ABC

Searching	Replace with	Expected	Things Happeded
(A)	#	#BC	A#BC
(A)(B)	##	##C	A##C
(?:A)	#	#BC	#BC
(A)(B)	\0	ABC	ABC
(A)(B)	\1	AC	AC
(A)(B)	\3	C (as in gedit)	C

As in table the first two rows don't look right.