extensions/markdown-language-features/src/preview/previewManager.ts/MarkdownPreviewManager/_createNewDynamicPreview
class MarkdownPreviewManager:	private _createNewDynamicPreview(
		resource: vscode.Uri,
		previewSettings: DynamicPreviewSettings
	): DynamicMarkdownPreview {
		const activeTextEditorURI = vscode.window.activeTextEditor?.document.uri;
		const scrollLine = (activeTextEditorURI?.toString() === resource.toString()) ? vscode.window.activeTextEditor?.visibleRanges[0].start.line : undefined;
		const preview = DynamicMarkdownPreview.create(
			{
				resource,
				resourceColumn: previewSettings.resourceColumn,
				locked: previewSettings.locked,
				line: scrollLine,
			},
			previewSettings.previewColumn,
			this._contentProvider,
			this._previewConfigurations,
			this._logger,
			this._topmostLineMonitor,
			this._contributions,
			this._opener);

		this._activePreview = preview;
		return this._registerDynamicPreview(preview);
	}