DHTMLX grid column freeze option - Header Column Overlap

Suite and Optimus Suite 5
#1

We have created a grid and we are trying to implement column freeze option in it.
we are trying freeze first 3 columns using below code

mygrid.splitAt(3);

so when we do this the grid gets split into two and freeze is working but when we try to do horizontal scroll the header in leftbox(First 3 fixed columns) is overlapping with the headers in right box(remaing columns).
I have Attached screenshot of the issue. Checkbox, Num, Status are the first 3 fixed columns and others are remaining column.

Please suggest options to resolve this issue.

#2

Attached the screenshot of the issue

#3

Unfortunately the problem cannot be reproduced locally.
Could you please, provide with a complete demo or share with a demo link, where the problem cane be reconstructed.