Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> I enhanced the docstring and rewrote the command so that it does
>> not use a temporary keymap.
>
> Not using a temporary keymap means reverting to the old code: please
> explain precisely why using a temporary keymap is a problem (there are
> good reasons to use it: e.g. it makes key-translation-map and friends
> work correctly).

Here is another patch, using ̀set-temporary-overlay-map'.

It fixes the problem with the message disappearing.

It fixed another problem: the fact that in the current version,
INC is always 1 when using the command repeatedly, as we would
expect 

C-u 4 C-x C-+ +

to increase by INC = 4 then again by INC = 4 again -- right now
it increase by INC = 4 on the first hit, then INC = 1 on the 
second.  

It also changes the behavior regarding C-x C-0, which ends
the loop.

Let me know what you think,