OpenEdge 11.x, Visual Designer, SmartWindowForm
Developer was trying to add a User Control to a SmartWindowForm using the "Insert UserControl" designer verb (property sheet of the Form in the Visual Designer). The "Select UserControl class" Dialog did not show any user control. Developer confirmed that User Controls exist and r-code was present.
In this particular project, the source code and r-code have been stored in two different sub-folders of the developer studio project root. The "Select UserControl class" is based on the Consultingwerk.Util.ClassHelper class which requires to locate the r-code of the classes.
Add the base folder of the r-code (rcode, bin, ...) to the .classpath file. Details about maintaining the .classpath file can be found in the article: Support for multiple project roots and the Shared AVM feature
In this particular code, the .classpath file needed to be configured like this: