question regarding `c' operator acting on rectangular region

[joerg van den hoff]

rarely using rectangular regions (and when, then for deletion), so I was 
surprised by the following:

issuing something like

c^Aqjq

to select a rectangle with a width of one character and a height of 2 lines
and trying to replace the rectangle by a multicharacter string fails. only the first character of 
the replacement string specified in response to the "Rectangular text:" query is inserted.

e.g. with an input of

1 2 3
1 2 3

and selecting the 2nd column as rectangle and trying to replace the 2s by "abc" 
results in

1 a 3
1 a 3

I would have expected the text to the right of the rectangle to be shifted to 
the right to make room
for the full replacement string?

questions:

* am I doing it wrong?

* if no, is this to be expected behaviour or a bug?

* if not a bug, is there a canonical way to achieve the desired edit result, 
i.e.

1 abc 3
1 abc 3

in this example?

thank you
joerg