This happened sometime in the past couple of releases. We are not sure yet if it was with the WordPress update or SLP update.
We are working on a patch to SLP so that the admin tabs do not lose content when using a non-English site. Changing the site to English (or your user) will bring back the tab content until we figure out what needs to be patched.
We expect to have an SLP 4.9.1 patch out in the next 7-10 days, immediately after our Power 4.9.1 update is released.