Default landing view is not working after upgradation.

Hello All, 

Recently my online CRM has been upgraded from  CRM 8.2 to 9.0.

After some customisation like by default landing page was not set to dashboard and and a deult view inside this.

I tried to change it by going to customisation --> dashboard -- selected view to set it as default view.

But it didnt worked. After that I noticed XRM--> my Open Leads view is still set as default .

I tried to remove it to set as default view but i couldnt.
Pls help me how i can achive  this.

Thanks