Hi Alfio,
The "Save Configs" as far I could see, works considering User and Page, as you are using the same page to handle different columns definition, right after grids renderization, the configuration feature note that you have a config saved and tries to apply it .
As we change grids structure, some of the columns are no more available.
The save configs will save your grid configuration per column (header, sort and filter definitions, position, visibility etc), the key used to do it is the JSONField, in your case "Col1", "Col2", "Col3", "Col4" and "Col5".
So when you save configuration for a grid with 5 columns, and you change to 2 columns, the code will render untill "Col2", when the configs are applied the "Col3" isn't available, and we have an error.
I will open a Support case so your case can be analyzed, by now, not to let you stuck waiting for us, I would suggest one of the solutions bellow:
- Create different pages depending on the structure you want. In this case the Save configs will work just perfectly
- Maintain the different structures on the same page, but remove the "Save Config" button
Hope I could help you