When you click on , you should see concrete, steel and timber qualitities.
When you click on , you should see a long list with a lot of cross-sections.
If one of the materials/ cross-sections is missing, you unintentionally defined a filter in the material (or section) Library.
- Go to Edit > Material (or Section) library.
- On the left side at the bottom, you have a button Clear all. Click on it.
- Close the Material (or Section) library.
- Check if the material (or cross section) is now available with (or ).