It sounds like you’re referring to a specific software update for Tekla Structures 21.1 (the SR1 update, including help files for version 33 of the documentation). That particular release dates back to around 2016–2017, when Trimble was still refining the 21.1 branch.
Note: In a service pack installation, you typically cannot change the installation folder; it will overwrite the existing 21.1 directory. Tekla Structures 21.1 SR1 Update with Help 33...
Tekla Structures 21.1 Service Release 1 (SR1) update is a maintenance and enhancement release that includes various fixes and improvements to the modeling and drawing interfaces. One of the most highlighted useful features is the introduction of a more interactive Instructor side pane It sounds like you’re referring to a specific
Install Help 33:
Tekla Structures 21.1 Service Release 1 (SR1) is a legacy maintenance update that addressed stability, API, and modeling issues, including enhancements to CatalogHandler and component management. As of December 31, 2022, version 21.1 has reached its End of Access, and users are encouraged to upgrade to newer versions for continued support. For the full technical release notes, visit Tekla Developer Center. End of life announcements archive - Tekla While moving a steel beam or rebar group,
or through the Windows Start Menu under Tekla Structures apps. Instructor Side Pane
Tools > Options > Numbering and click "Restore Defaults". The SR1 patch changes default parameters retroactively.