Bugfix for webview in report_plot.

Author: thocevar

Orange/widgets/report/report.py

@@ -184,7 +184,7 @@ def report_plot(self, name=None, plot=None):
         elif isinstance(plot, WebviewWidget):
             try:
                 svg = plot.svg()
-            except IndexError:
+            except (IndexError, ValueError):
                 svg = plot.html()
             self.report_html += svg