Can't Add Dashlets to the Dashboard

I can’t add Dashlets to the Dashboard and dashboard displays that " " .
Herewith I had attached the Snap of the screen when clicking the Add dashlet button. It seems to be in loading.

Vimalan, i tested described case on recent version of SuiteCRM(7.7.8), and not appear, can you tell me the version SuiteCRM you use, and also some enviroment details, such as Browser name and version, PHP and SQL version, and OS?

Thanks for your Kind reply Jezry. Herewith I’ll mention the details that you asked.

  1. SuiteCRM version 7.7.8
  2. Browser - Google Chrome (Version 55.0.2883.95)
  3. Xampp - 5.6.28
  4. OS - OS X El Capitan (Mac)

Vimalan, on SuiteCRM GitHub repository we have some raised issues related to your case,

If you use Suite 7 or Suite R theme, please try this fix:
If above doesnt work, please try this fix: