How to navigate from a VF page to some other SF page without nested header and sidebar?

Question

I have a Visualforce page with its own controller. One of the buttons on the page must go to a standard Opportunity page. I thought I would use this:

return new PageReference('/' + oppId).setRedirect(true);

but that only works partially: the Opportunity page is displayed with its own header and sidebar, so I see a header and a sidebar inside a header and a sidebar. Doing setRedirect(false) doesn't make any difference.

How do I refresh the complete page, how do I navigate away from the current page?

Answer 1

When you are returning your page reference add the URL parameter

isdtp=vw

Although not officially support it hides the sidebar and header in classic. Also depending on the parameter you use, you loose some styling and functionality:

https://www.ca-peterson.com/2011/12/08/the_magic_isdtp_param/

Or you can create a vf page

<apex:page standardController="Account" showHeader="false" sidebar="false">
 <apex:detail />
</apex:page>

And redirect to it

Answer 2

What I had was a button that redirected to a VF page. The button has as property: "keep existing header and sidebar", the VF page had as property: "showHeader="false" sidebar="false""

But it must be the other way around: the button must open the VF page in a new/empty page and the VF page must have a header and sidebar.

The first way constrains all subsequent redirects, you can never 'escape' this constraint and return to the full page.