I am working in QGIS 3.8.3-Zanzibar on a shapefile with polygons.

I am zoning by selecting the polygons and giving each group a different number (a zone code). 

In order to visualize it, I have a Category Thematic map with the zone number, so I can easily see the different groups I am creating. 

[![zoning progress][1]][1]

But, as I keep on making groups (that is, giving other zone codes to the polygons), it is hard to visualize the result unless I manually update the thematic map.

**I would like the map to dynamically change its colours as I change the zone numbers**. Until now, I have to re-classify the categories of the thematic map, as it only clasiffies with the existing numbers (zone codes) but the new ones I give out, the all go to the group of "all other..."

[![categories and "all other..."][2]][2]


  [1]: https://i.sstatic.net/lzF6N.png
  [2]: https://i.sstatic.net/0cubJ.png