As PeopleSoft moves from Classic to Fluid, you have likely noticed the missing New Window link. Why is it missing? I can only speculate.
When considering mobile, perhaps it makes sense to drop the New Window link. Mobile devices have limited screen real estate. Why waste it with a link you will likely never use on a mobile device? On a desktop, however, the New Window link is irreplaceable. So... what to do? How can you open a new window? You probably already know if you just open a new window without that special New Window link, your old window session will cease to exist. You know that you will receive the dreaded "... return to most recent active page..." message. Does that mean you can no longer have two active PeopleSoft windows? There is a work around that is documented in various places around the web. In short, the answer is to copy the current URL, open a new tab, paste the URL into the address bar, and then append _newwin to the site name. Before reviewing some examples, let's discuss what is going on and why this is necessary.
The PeopleSoft app server is stateless. App server connections are often pooled and used upon request. However, we know that component buffer state is stored somewhere. If not at the app server, then where? At the web server. As with any J2EE application, PeopleSoft uses web server sessions to store state (which is why load balancers must use sticky sessions, etc). The details here aren't exact, but metaphorical. PeopleSoft partitions web server session state into state blocks. A user may have multiple state blocks. The web server identifies the appropriate state block based on an identifier in the URL. When you click the New Window link, the link's URL pattern instructs the web server to generate a new state block. We can replicate the New Window link behavior by simply modifying a PeopleSoft URL. Let's review an example. Let's say you have a Fluid URL that looks something like this: http://hr.example.com/psc/ps/EMPLOYEE/HRMS/c/EL_EMPLOYEE_FL.HR_EE_ADDR_FL.GBL. The highlighted part between the servlet (psc) and the portal (EMPLOYEE) is the site name (ps). All we have to do is add _newwin to the site name. Accessing a URL such as http://hr.example.com/psc/ps_newwin/EMPLOYEE/HRMS/c/EL_EMPLOYEE_FL.HR_EE_ADDR_FL.GBL will instruct the web server to generate a new state block, perhaps something like http://hr.example.com/psc/ps_23/EMPLOYEE/HRMS/c/EL_EMPLOYEE_FL.HR_EE_ADDR_FL.GBL.
It certainly isn't as simple as the New Window link, but it is better than nothing. For a more permanent, user friendly method, take a look at Sasank's post Fluid UI - New Window Feature - Workaround.
Edit: I created this post because a lot of people I meet aren't familiar with the "New Window" trick. One very important caveat when working with classic pages: The URL in the header may not match the transaction URL. This appears to be tools release dependent. After PeopleSoft implemented "Partial Page Rendering" with a constant header and iframed content, the URL for the content area would change, but the URL in the address bar did not. What this means is simply copying the URL from the address bar and changing it to include '_newwin' will create a new state block, but that new window may point to different component from the original window.
Source: Jim's PeopleSoft Journal