Convert a multipolygon relation into a regular polygon

I can convert a usual polygon into a multi-polygon quite easily with Ctrl-B. All tags of te polygon become tags of the new relation.

But how do I do the opposite? Currentyl I have a lot of relations that consist of a single polygon, and I want to remove the relation and have all tags moved to the polygon.

Is there any way to achieve that?

There’s a JOSM plugin called “relation toolbox” (reltoolbox) that lets you do this. You have to select a relation and then you can right-click on the relation in the relation toolbox panel and select “reconstruct multipolygon”.

It’s best to confine such changes to a small area unless all nearby mappers agree that it is needed. Otherwise the next mapper is likely to come along and convert all adjoining polygons back to multipolygons.

Thanks, I’ll try that.

Don’t think that anyone would convert it back - these are remainers of a huge automatic import that often created unnecessary multipolygons.