Hi Himanshu,
sorry your description is not clear. Out of the above attached two screenshots, second one is standard and the first one is custom. The only one difference between these two is the theme. When you make changes in theme it doesn't affect the standard one. The changes which you've made in the custom theme will only be reflected in the portal when it is assigned to end user.
Are you able to see the custom theme changes in ESS screen after you assign the custom theme to end user?
what is the difference between "Custom theme assigned to users and Custom theme assigned to portal"?
Regards
Kamal