 
 	override func sessionChanged() {
 		super.sessionChanged()
+		loadPreviewIfNecessary()
 	}
 
 	// MARK: - notification handlers

			emptyNavigations.remove(navigation)
			return
		}
		Log.info("did finish webView load")
		guard let _ = parsedDocument else { return }
		updatePreview()
	}

			currentPreview = nil
			return
		}
		loadPreviewIfNecessary()
		if  var previewInfo = previewData[fileId]
		{
			// already have preview info
