Visual indications that an evaluation is ongoing are too subtle

[martinmcclure]

Currently, on any user action that causes a call to the server, the pane header text, and some other text, dims until the server response is received and processed.

For short operations like building and fetching inspector services when clicking on an inspector field, this is probably enough. For long operations like an evaluator evaluation that runs several seconds or more, it is not enough. It's not easy to tell by looking whether the evaluation is still running.

Perhaps a visual overlay of the evaluator's text field? Or a "running" icon in the evaluator subpane's header? Need to be careful to not make the visual effect too loud, or it will get annoying. Differently annoying.