grid customGroupFormat is having weird behaviour

Hi,
i have the following code

summeryStepsGrid.customGroupFormat=function(name,count)
{            
      // some code goes here...
      
      var chartId = "legChart_" + name;
      var groupLabel = "<div id =' chartId' ></div>"; 

      return groupLabel;
 };

Later i use the summeryStepsGrid.groupBy() function (this grid will never be ungrouped again) and then call a function that populates the div with id = chartId.

Everything seems to work ok until i deside to expand some of the groups. All the content inside the chartId div disappears because the customGroupFormat function gets called. This is strange for me because i do not ungroup the grid. I simply expand some of the group.

Any solution on how to get this fixed?

P.S. I am using version 3.6

Unfortunately the issue cannot be reproduced locally.
If the problem still occurs for you, please, provide with a complete demo/demo link, where the problem can be reconstructed.
Here you can find a tutorial about creating a complete demo:
docs.dhtmlx.com/auxiliary_docs__ … pport.html