The issue you mention is related to Glimpse making changes to the Routes configuration which broke the WebApi Help Pages, fortunately that issue has been solved in the meanwhile.
Based on your question, I assume that you want to see Glimpse diagnostics for WebApi related calls? Unfortunately Glimpse v1.8.4 does not support WebApi requests.
The good news is that support for WebApi is being added as we speak. You can check the pull request to see how it's going and when it's expected to be released.