[Lens] Add an unsaved changes badge in Lens editor, same as dashboards do

[majagrubic]

Kibana version: 7.8

Browser version:
Chrome 81

Browser OS version:
Mac OS 10.14

Original install method (e.g. download page, yum, from source, etc.):
Cloud

Describe the bug:
When editing a Lens visualization, navigating away from it to another app (eg. Dashboard) and returning back to Visualize, visualization listing page is displayed, instead of a previous Lens visualization. Also, there is no Lens visualization in "recently viewed" items. This works for all other visualizations.

Steps to reproduce:

1. Go to Visualize, Lens, create a new visualization or edit existing
2. Select Dashboard from the new nav bar
3. Select Visualize from the the new nav bar - visualize listing page is displayed

Expected behavior:
Previously edited Lens visualization is displayed.

[elasticmachine]

Pinging @elastic/kibana-core-ui (Team:Core UI)

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[flash1293]

I'm not sure whether there were discussions around this behavior, but it's expected - as Lens is a separate app it would have to handle these features itself, but it doesn't at the moment. I agree we should make the behavior more consistent here though.

[flash1293]

I'm a little on the fence whether this is a bug or an enhancement :D It was never intended to work, but it's definitely not what a user would expect. I lean more towards enhancement, so I'm going to relabel, but no strong opinion.

[wylieconlon]

Adding to Editing experience

[mbondyra]

How do we want to solve this problem? I see two possible solutions:

• popup window about navigating away (maybe it can be the first step)
• keeping state of unsaved lens visualisation somewhere, (local storage (would be aligned with undo/redo) or a 'ghost' saved object)

[flash1293]

Option 1 seems like a very good short term solution, for option two we should think about the topic in context of whole Kibana how we want to make behavior consistent (currently it's a mess and I would like to avoid adding yet another inconsistent way of handling it).

[ghudgins]

use case where this could be useful - error cases where we link users off to settings to do something

we had trouble thinking of more use cases where the legacy visualizations / tsvb functionality is desirable. we do have concerns that the behavior can be annoying and a bit unexpected

@AlonaNadler has anyone ever complained about this in lens from your standpoint? we're aren't convinced this is a problem for people because lens has been missing this for some time

[AlonaNadler]

I haven't heard anything about this issue. Let's go with your judgment here

[ThomThomson]

It's currently pretty easy for users to lose unsaved changes in lens. I think this will start to become more annoying as more complicated features and settings are added to lens. Formulas for instance, could be a pain to re-write when lost because the user navigates to another page and back.

Dashboard uses a pattern where unsaved changes are saved to session storage based on the dashboard id, so the latest 'unsaved changes' can always be restored when editing any dashboard, or creating a new one. I wonder if it would be worth eventually implementing something like this in Lens.

[dej611]

In order to provide better transparency of priorities, issues that will not be prioritized within the next 24 months are being closed.