Grid Column Resize Style
This option controls the behavior of grid column resizing, both in the Visual Designer and at run time when the "resizable columns" grid feature is enabled.
Possible values are:
"simple" - the grid maintains its total width; space needed to resize a column is borrowed from the next column
"excel" - columns that follow the column being resized are moved, similar to how Excel column resizing works (this option is the default)
Example:
pui["grid column resize style"] = "simple";
Where do you save this configuration option?  Here