vscode.ViewColumn doesn't work as expected

[Sneezry]

• VSCode Version: 1.21.1
• OS Version: Microsoft Windows [Version 10.0.16299.248]

Steps to Reproduce:

1. install Visual Studio Code Tools for AI
2. Ensure no document open
3. Execute AI: Open Azure ML Sample Explorer twice
4. Two Azure Machine Learning Sample Explorer will open

Does this issue occur when all extensions are disabled?: N/A

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This issue is cause by vscode.ViewColumn.Two. When we want to open a document in the second column, the first column should exist, and if there is no column, the document will open in the first column, even if we are clear to open it with vscode.ViewColumn.Two. I believe this is as design, but it doesn't make sense.

What I expect is, when there is not column, the document will also open in the second column, and the first column is hidden, but not replace the second column with the first one.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Idea for enhanced editing scenarios: dynamic, nestable rows and columns for editing, analysis and visualisation. (#13821)

[jrieken]

What I expect is, when there is not column, the document will also open in the second column, and the first column is hidden,

Not sure what that means? Do you want an empty first column?

[Sneezry]

When I open a document in the second column vscode.ViewColumn.Two, then it should really open in the second column.

If there's no document open, after I open a document in the second column, only one column will show (this is as expected), but the shown column should still be vscode.ViewColumn.Two as it is clear in the code:

And when I open a new document in vscode.ViewColumn.One, I expect vscode open two columns:

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Why I request this change?

The issue we have in fact is unexpected duplicate explorers:

Generally, when the user has document open in vscode (text document, or welcome page), the explorer will open in the second column. And even the user run open explorer command multi times, there will be only one explorer.

However, if the user has no document open, and run open explorer command twice, two explorers will open in the first and second column.

[jrieken]

When I open a document in the second column vscode.ViewColumn.Two, then it should really open in the second column.

The workbench currently cannot do that as columns are not static but dynamically added while editors are opened.

You should be looking at #45994 which is about improving the webview-api and which will let you know in which column the webview currently shows.

Assigning @bpasero for the static workbench layouts

[bpasero]

Allowing arbitrary editor layouts is covered in #2755

[Sneezry]

Emmm, I do not agree this issue is duplicate with #2755. As an extension developer, I cannot ask my users to change their vscode config to make the extension work as expected.