DHTMLX Grid Issue

We need to get your support urgently because we faced several issues about DHTMLX Grid during the development for LGE Global portal system.
We listed up the key issues we encountered in the below. (Grid issue)

We tested your grid under all the Explorer users’ cases (no issue for Chrome users)

  1. Issue for extremely low scroll speed (White screen shows when moving scroll up & down in the grid)
  2. Issue for Header menu’s open & close speed (encountered many cases for browser freezing)
  3. Issue for edit function’s efficiency (extremely low response speed to user’s editing)

This is the case when we consider 800 rows with 65 hidden columns
(You can refer to the attached file for detail information)

We also have another issue for managing progress bar.
Now we try to do form submit using iframe when we use toExcel() function.
Please advise us how to hide progress bar right after download is finished.

Best Regards, tokybob.