Hi,
I’m new, so excuse me for a such basic question…
I’ve updated a map (#12758446) and the modification continues to appear as “update in progress”.
But I’ve yet saved the modifications, so why the update is not finished ?
Thanks 
Hello There,
Welcome to OSM, please first realise this mapping business can become addictive, be warned.
I don’t know why the “update in progress” still persists but here are a few observations of the changeset. Firstly amenity=hospital is wrong as I think you suspect, amenity=retirement_home seems to suit your purpose http://wiki.openstreetmap.org/wiki/Tag:amenity%3Dretirement_home
Secondly the area needs to be tagged “building=yes” if indeed it is a building.
Regards
Bernard
I’m not sure what language you are using on openstreetmap.org, you may have translated the message incorrectly. I think you are referring to the “still editing” message.
When you save some changes in Potlatch 2, then the changeset (which is a group of edits) will remain open. This means you can continue with more changes, then save them in the same changeset. In Potlatch 2, you can close the changeset by pressing “C”. Or the changeset will close automatically after an hour.
So usually you don’t need to worry about it, just save your edits in Potlatch. Note if you are doing different types of edits, it may be helpful to group them into separate changesets, then you can add a relevant comment for each part.