Create workbench.editor.openPositioning pendant for tab groups

[EnCey]

Steps to reproduce

1. Open a markdown file via explorer (ctrl+shift+e) and then its preview (ctrl+k, v)
2. Open a second markdown file via explorer
   Result: markdown file opened in a new tab in the left tab group, its preview replaced the previous one in the right tab group
3. Open a third markdown file via explorer
   Result: markdown file opens in the 2nd tab group next to the preview and spawns a 3rd tab group

Expected behavior

Markdown files should always be opened in the left tab group and their preview in the 2nd tab group.
This behavior is independent of other tab settings (open markdown file as preview, do not use tabs at all, etc.)

The problem

It seems that after step 2) the preview tab in the 2nd tab group has focus. This is why in step 3), the markdown file is opened in the 2nd tab group.

This process can be repeated indefinitely. After step 3), the preview in tab group 3 has focus. If another markdown file is opened, it will open in the 3rd tab group and spawn a 4th group.

Why this matters

When editing markdown files in a folder, you often have to switch between files.
I cannot fathom a scenario where someone would want a new markdown file to be opened next to a preview tab, effectively hiding the preview and displaying the 2 markdown files side-by-side, plus showing a preview of the 2nd in a 3rd tab group.

Possible solution

Create a setting similar to workbench.editor.openPositioning, only that it controls which tab group is used when opening new files. I.e. when setting this to first it would solve the problem described here.

[vscodebot]

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

• Can't drag Markdown preview to start a new editor group (#25854)
• Markdown preview: don't show editor if (1) it's hidden (2) user clicks a link to another local markdown file (#38100)
• Open Markdown links inside the preview pane itself as Markdown preview (#37883)
• Markdown Preview: Links to markdown files in the workspace should also open in the preview (#19339)
• Add way to open Markdown links in a different editor group (#26659)

[EnCey]

This is perhaps related to, but not a duplicate of #19339.
The issue here is simply that you cannot quickly open a bunch of markdown files via the explorer view without ending up with 3+ tab groups.

[mjbvz]

Closing due to lack of further feedback since this was opened 2 years ago