Improved error handling of re-numbering motions of a category.
Improved error handling of re-numbering motions of a category.

jwinzer/OpenSlides,emanuelschuetze/OpenSlides,boehlke/OpenSlides,jwinzer/OpenSlides,emanuelschuetze/OpenSlides,boehlke/OpenSlides,normanjaeckel/OpenSlides,normanjaeckel/OpenSlides,emanuelschuetze/OpenSlides,CatoTH/OpenSlides,tsiegleauq/OpenSlides,jwinzer/OpenSlides,boehlke/OpenSlides,OpenSlides/OpenSlides,FinnStutzenstein/OpenSlides,ostcar/OpenSlides,FinnStutzenstein/OpenSlides,ostcar/OpenSlides,tsiegleauq/OpenSlides,CatoTH/OpenSlides,normanjaeckel/OpenSlides,FinnStutzenstein/OpenSlides,ostcar/OpenSlides,FinnStutzenstein/OpenSlides,jwinzer/OpenSlides,CatoTH/OpenSlides,CatoTH/OpenSlides,boehlke/OpenSlides,normanjaeckel/OpenSlides,OpenSlides/OpenSlides,emanuelschuetze/OpenSlides,jwinzer/OpenSlides,tsiegleauq/OpenSlides