If your project contains VHDL 2008 files, you also have to use the 2008 version of the STD and IEEE libraries.
- Make sure your project is set to VHDL 2008 :
Right click your project and select Properties > VHDL version
- Right click the Common Libraries folder of your Sigasi Studio project and select Set Library > Reset Common Libraries
Sigasi Studio 3.6 will offer a quick-fix to make this easier.
- How to set up the UVVM Library in Sigasi Studio (blog post)
- Customizing documentation from Sigasi Studio: easier than you think (blog post)
- Customize documentation from Sigasi Studio using the Document Object Model (blog post)
- Generate documentation in Sigasi Studio (blog post)
- Using the util package from Modelsim with VHDL 2008 (blog post)