When you add an external tool to a site from following step, and then, edit that page name from pageOrder tool, you click on the tool with the newly changed name, instead of launching the external tool, it just load the site within the frame as per the screenshot.
I did it on the nightly trunk build as of today. Here is how I reproduce it:
1. create a course site.
2. go to newly created site -> Site Info -> External Tools
3. click on Tools Available in System -> Add External Tool to System to add an external tool
4. click on Tools Added to Sites -> Add Available Tool to Site -> select the external tool -> check the checkbox of Add Site Link -> click save
5. Click on the added tool in the left navigation panel, you can load the external page in the iframe.[Good]
so far so good. Next is to produce the issue:
6. Back to Site Info -> Page Order -> find the external tool you added in step 4 and change its name
7. The name was updated in the left panel, but when you click on the tool, you load the whole site in the iframe instead of expected external page.[BAD]