Cannot enable resizing of Gantt grid and columns

I am using the Gantt standard edition v5.1.0 and would like to enable the feature for users to resize the grid and its columns. But when I set the resize config options, the resizing widget does not appear. Can someone explain what I am doing wrong. Below is the code that reproduces the problem.

Hi Mark,

At present time gantt.config.grid_resize is deprecated (maybe in future we will add it again, maybe not).
As an alternative way please use the gantt.config.layout instead and specify grid and resizer configurations with the necessary values.
Here is a demo, check how it works:

Thank you for the suggestion. However, when I tried it in my environment it did not work. The difference appears to be the dhtmlxgantt versions. In the code snippet you used 5.1.2 from the cdn which the license at the top of the file says can only be used on the site. I am using the standard (open source GPL v2 license) version 5.1.0 files which I downloaded using the following link
Is there an alternative location where I should be downloading the 5.1.2 version?

{ resizer: true, width: 1 } inside grid.config.layout didn’t work for me as well. Also, my code already had these properties set, but nothing changes with them.

Yes, resizing works only in Pro versions. You can download the released 5.2 version if you follow that link. But the Standard version doesn’t have resizing feature.
Please check the following snippet that demonstrates how to dynamically resize the grid in the Standard version:
Using it you can create your own solution.

how to do with mouse resize cursor, please?

When the mouse is over the resize elements, the cursor style changes:

If you want to show a different cursor, you need to change the cursor style rule:

If you want to keep the resize cursor until the resize is complete, you need to modify the style rules. And the easiest way to do that is to use the onColumnResizeStart, onGridResizeStart, onColumnResizeEnd, and onGridResizeEnd events:

Here is an example of how it can be implemented: