User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36

Steps to reproduce:

It would be helpful to see a tooltip containing relevant context about the value of an ObjectInspector tree node. Chrome is the benchmark here in providing helpful tooltip values for their watch expression nodes.

1. Navigate to http://todomvc.com/examples/jquery/#/all and add a breakpoint in app.js at line 128.
2. Add a new todo item and trigger the breakpoint.
3. Hover cursor over any value of any key in the scopes or watch expressions secondary panels.

Actual results:

Actual Results:
In Scopes panel, no tooltip is displayed for most rep types. Some Objects include a [more...] tooltip and some Arrays include [more...] tooltip, but majority of rep types do not display a tooltip with relevant value.

In Watch Expressions panel, all items include a tooltip containing the item key, not the value.

Expected results:

Expected Results:
When hovered, tree items in the Watch Expressions and Scopes secondary panels should provide a helpful contextually-relevant tooltip containing appropriate value, similar to Chrome's implementation.

I'm already working on this as part of a different bug that has diverged from its initial intent too far to continue to be considered the original bug. I've been working on adding contextual tooltips to Watch Expression values (specifically ones that are truncated when too long for the Watch Expressions secondary panel). To do this in a flexible and more generally helpful way It would make sense to pass a tooltipTitle boolean param into the rep itself from the parent(s) component instance. If true, the Rep rendered would add a title attribute to the span rendering the Rep value with the appropriate value for the type of Rep.

I also believe that this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1557890 is the same intent but specific to particular types of reps.

Original Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=915854 led me down the rabbit hole into a refactor of the reps.js code to accommodate a new title tag element in each rep per phabricator commend by :davidwalsh here: https://phabricator.services.mozilla.com/D35508

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (non,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

The priority flag is not set for this bug.
:jlast, could you have a look please?

For more information, please visit auto_nag documentation.

https://hg.mozilla.org/mozilla-central/rev/e2438f25cfb3

I decided not to explicitly document this feature. It will be easily discoverable by users; nobody's going to learn about it from reading documentation.