FIX: collapsed and expanded treeview state is preserved when saving

[smnwttbr]

Description

Fix for ISXB 1164

I've removed (unused) methods related to saving the expanded state of the tree. These might have been an artifact from an earlier implementation, any any case, these were unused.

I changed the guidToId caching mechanism to use guid.GetHashCode() so that we get a deterministic guid->int mapping.

Testing status & QA

Ran local package tests.

Overall Product Risks

• Complexity: 0
• Halo Effect: 0

Comments to reviewers

Please describe any additional information such as what to focus on, or historical info for the reviewers.

Checklist

Before review:

• Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • JIRA ticket linked, example (case %%). If it is a private issue, just add the case ID without a link.
  • Jira port for the next release set as "Resolved".
• Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

After merge:

• Create forward/backward port if needed. If you are blocked from creating a forward port now please add a task to ISX-1444.

[ekcoh]

Look trough the code (didn't run it) and in general I must say I have love PRs that remove more lines than they add :) Not sure I fully understand how this rather compact PR solves the problem though.

[ekcoh]

Code changes LGTM if it works. I noticed you have changed to a index based id it seems so would recommend covering expansion state robustness in the tests, e.g. what happens if you expand two branches and then insert a new branch between them? So just want to sort this out before approving.

[ekcoh]

Unfortunately UI tests are failing based on this change it seems, see CI jobs.

[ritamerkl]

I would recommend checking if the id's need to be consistent between rebuilds - some functionality may use the id's where the information might get lost assigning new ids.