I'm trying to debug a project which includes an external jar (which i also developed). While debugging, I would like to be able to step through the source code of classes within that jar and debug normally, however I am receiving the following error message when trying to inspect variables:

Unable to evaluate the selected expression

To perform an evaluation, an
expression must be compiled in the context of a Java project's build path. The
current execution context is not assoicated with a Java project in the
workspace.

Here is what I have to to attempt to rectify the situation so far:

1) Exported the external JAR file with source.
2) Imported the jar file into the new application
3) Set the "Java Source Attachment" option on the jar file to point to the src folder of the actual source of the jar file
4) On the DEBUG options (as Java Application)
a) added the jar file to classpath
b) added source folder to classpath
c) added source folder on source tab
5) Tried importing the jar file as an external jar or as a library containing the jar
6) Tried with/without checking the jar file on the Order and Export tab of Java Build Path

No matter what I try, I keep getting the "light blue" line identifier when debugging instead of the green line identifier (and all the benefits that come with it). I can see the source, but that's about it.

Any assistance is appreciated.