Test Custom View API improvements

[sandy081]

Refs: #48198 #49311 #50662

• anyOS @isidorn
• anyOS @weinand

Complexity: 2

Write an extension that contributes a tree view to the Explorer. Refer to documentation and ftpExplorer.

• Test listening to onDidChangeSelection event when the selection changes.
• Test visible property and the corresponding onDidChangeVisibility event are working as expected when the tree view contents are visible or not. NOTE: visible is false when the tree view is collapsed.
• Test passing focus flag to reveal api and make sure that revealed element is focused - reveal(element: T, options?: { select?: boolean, focus?: boolean }): Thenable<void>;

[weinand]

@sandy081 Writing an extension can only have a complexity of 3 and more...

[isidorn]

@sandy081 please provide an extension that is creating a tree view, since the one you attached is not using the new createTreeView api.
Writing a new extension that does all this seems like a much higher compleixty
Thanks

[weinand]

@isidorn I've updated https://github.com/weinand/vscode-processes to the new API. You can use this as a sample.

[isidorn]

@weinand thanks!

[sandy081]

@isidorn FTP Explorer uses the Tree view implementation. Updated the description to use that sample.