beta version (5.1.1130.26)

[Admini]

yes
for example this
https://chromewebstore.google.com/detail...animbopamb
https://www.upload.ee/files/16403409/Net...r.zip.html
if you replace “open in tab” with true in the manifest, it still opens in a small popup window https://i.imgur.com/iw6XU7X.png
but on stable cent I have it like this https://i.imgur.com/hxQKqWW.png

As I tested, this work normally.
You may need to delete the "_metadata" directory and reload the extension after changing manifest.json