On the UMP portal, if I check the option Performance Reports on the menu bar, the application does not work. The UMP open a blank page.
This being a problem with my portlet?
That is odd, if the page is blank maybe the PerformanceReportsDesigner portlet was deleted for some reason? Have you tried manually adding the portlet back and then refreshing the page?
I go add the portlet, because the PRD portlet was deleted for some reason.
Great, I am glad it was quick fix and nothing critical.
Have you tried to clear the browser cache. I have had similar issue when using prod 8.0 and dev 8.2 with same browser and as far as I remember just clearing IE caches solved the issue.
Absolutely, clear the browser cache as a first attempt to fix. Also helps to try a machine that has never run any of the UMP portlets as a test too.