We've got support for showing multiple configs in a single view now, we should utilize it by adding a "Compare To" button on the resource config history page so that people can select older configs or the current config and diff them.
granted, we /can/ show multiple configs in a single view, but this isn't necessarily the same as what was originally envisioned for diffing them. last i spoke with greg, he wanted this to be a direct side-by-side view (constrained initially to 2 configs, perhaps 3 down the line). however, your suggestion is intriguing, and i won't discount it from potentially being a general solution for N-wise comparison.
This bug was previously known as http://jira.rhq-project.org/browse/RHQ-1704
mass add of key word FutureFeature to help track
Created attachment 487647 [details] compare config screen snapshot this is now supported in the GWT UI. In fact, we can compare N configs. If I am viewing a config history page, I can select N history items and I can view diffs (shows in red font, where same values are shown in a black font). See attached screen for an example.
verified the feature is added. changed configuration of RHQ Agent changing the configuration. additionally testest that failed save configuration changes do not show up on the compare tool.
Bulk closing of issues that were VERIFIED, had no target release and where the status changed more than a year ago.