4. For the final step to adjust the screen layouts, identify the Web Blocks that are set in the Blank Screen/List Screen/Show Screen/Edit Screen properties of the Theme.
For each Web Block do the following:
4.1. Open it and find the MainContent placeholder in it;
4.2. Set the placeholder Style property to “MainContent ThemeGrid_Container” (without the quotation marks).
And that’s it. The Grid is on.
To finalize, just a couple of notes: