Referring to Nick's comment on issue 1112
\"I never expected anyone to ever delete 200 marker places. In fact, I'm struggling to see why you should when they are movable and capable of being converted to \"full\" places. \"
The reason why there are large number of deletions are a consequence of the change from Google maps to Open map tiles. This has caused a large number of canals and rivers routes to be shown incorrectly. Moving the markers one at a time is a very long process so it is easier to delete a section and recreate it.
i think Nick's point is that you can just drag them to the new location - the difference between GMaps and OSM isn't going to huge.