src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts/MainThreadDocumentsAndEditors/_findEditorPosition
class MainThreadDocumentsAndEditors:	private _findEditorPosition(editor: MainThreadTextEditor): EditorGroupColumn | undefined {
		for (const editorPane of this._editorService.visibleEditorPanes) {
			if (editor.matches(editorPane)) {
				return editorGroupToColumn(this._editorGroupService, editorPane.group);
			}
		}
		return undefined;
	}