extensions/markdown-language-features/src/preview/preview.ts/MarkdownPreview/_onDidClickPreview
class MarkdownPreview:	private async _onDidClickPreview(line: number): Promise<void> {
		// fix #82457, find currently opened but unfocused source tab
		await vscode.commands.executeCommand('markdown.showSource');

		const revealLineInEditor = (editor: vscode.TextEditor) => {
			const position = new vscode.Position(line, 0);
			const newSelection = new vscode.Selection(position, position);
			editor.selection = newSelection;
			editor.revealRange(newSelection, vscode.TextEditorRevealType.InCenterIfOutsideViewport);
		};

		for (const visibleEditor of vscode.window.visibleTextEditors) {
			if (this.isPreviewOf(visibleEditor.document.uri)) {
				const editor = await vscode.window.showTextDocument(visibleEditor.document, visibleEditor.viewColumn);
				revealLineInEditor(editor);
				return;
			}
		}

		await vscode.workspace.openTextDocument(this._resource)
			.then(vscode.window.showTextDocument)
			.then((editor) => {
				revealLineInEditor(editor);
			}, () => {
				vscode.window.showErrorMessage(vscode.l10n.t('Could not open {0}', this._resource.toString()));
			});
	}