How do I disable sorting for data grids on my dashboard?

You can use custom CSS to disable sorting for data grids placed on a dashboard. 

In your dashboard settings, you can place the following under the Custom CSS / Javascript section:

  <style>
  
  /* this is for preventing sort on header cell click */
 .body > .webix_dtable .webix_hcell {
     pointer-events: none;
 }
 .body > .webix_dtable .webix_hcell div {
     pointer-events: all;
 }
 
/* this is for hiding "sort" option from header context menu */
  .webix_scroll_cont a[webix_l_id="sort"] {
      display: none;
  }
  .webix_contextmenu {
      height: 180px !important;
  }
  
</style>