minor Insight code cleanup (rebased onto develop)



This is the same as gh-1395 but rebased onto develop.

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This is preparatory to other changes on a separate UI testing branch. It should not change behavior.

Test that the Insight left-panel is still arranged the same and works okay. Try tweaking `/application/entryPointHierarchy` in `container.xml`: integer values from 0 to 3 should exercise the different left-panel browser arrangements.