Open last seen editor, not last created

[colin-grant-work]

What it does

Fixes #9475 by changing the method by which the counter is found in EditorWidgetManager.getCounterForUri. Formerly, the largest existing counter was returned (most-recently opened editor), now the first entry for the widget in the array of recentlyVisibleIds is returned, instead.

This also required some modification of the logic for handling the recentlyVisibleIds. Previously, a widget would be removed as soon as it was no longer visible. Now the widget is removed only if it is disposed of. In addition, widgets are moved to the front of the line on activation, not only onVisibilityChanged.

How to test

1. Open a file (henceforth 'File A') in a full editor (not editor preview).
2. Then open another copy of the file to the side (ctrl + \) or through the command palette.
3. Open two new editors and put them in the tabbars with the existing editor widgets so that neither of the editors for File A is visible.
4. Click on the file node for File A in the navigator.
5. Whichever copy of File A was last visible / active should be revealed.
6. Try activating / hiding the editors for File A in different orders, and check that (5) still holds.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

Signed-off-by: Colin Grant [email protected]

[vince-fugnitto]

I confirm that the behavior works as expected using the described use-case.
The last visible editor is opened and not the last created 👍