PR# 19646 VTCT error, unknown class; class text is open and listed in Groups pane

Gobo class DS_AVL_TREE is open in an editor tab, and is displayed in the Groups pane, listed under gobo_structure/structure/table/DS_AVL_TREE.

Compilation has failed, having just added a local declaration for a reference to the class:

Error code: VTCT

Error: type is based on unknown class.
What to do: use an identifier that is the name of a class in the universe.

Class: EAC_TRANSACTIONS_IMPORT_GRID
Unknown class name: DS_AVL_TREE
Line: 141
      local
->      l_tree: DS_AVL_TREE [EAC_ACCOUNT, STRING]
      do
=======================
Compile: Find Added classes and recompile -- fails to resolve the problem
Project: Compile from scratch -- also fails to resolve the problem
The Gobo class is in the Project settings under:
$ISE_LIBRARY\library\gobo\gobo_all.ecf

It has happened before, several times, I think always with first use of a class from the Gobo libraries.

In this project, the Gobo libraries were [I think] added using the 'Add Library' popup from the Groups pane, right clicking on the intended parent cluster.

I will try to reproduce from a newly created project [this one has been in progress for a few weeks ...]

Problem, for the moment, solved by manually editing the project configuration file, and copy/pasting from the config file of an existing compilable project.
I was unable to find a GUI solution to resolving the issue ...

Added attachment for the project .ecf

Attachments for problem report #19646