rows specification of textbox input now changes codemirror box height properly

common/lib/capa/inputtypes.py

@@ -237,14 +237,15 @@ def textbox(element, value, status, render_template, msg=''):
     count = int(eid.split('_')[-2])-1 # HACK
     size = element.get('size')
     rows = element.get('rows') or '30'
+    height = str(int(rows) * 10)
     cols = element.get('cols') or '80'
     mode = element.get('mode')	or 'python' 	# mode for CodeMirror, eg "python" or "xml"
     hidden = element.get('hidden','')	# if specified, then textline is hidden and id is stored in div of name given by hidden
     linenumbers = element.get('linenumbers')	# for CodeMirror
-    if not value: value = element.text	# if no student input yet, then use the default input given by the problem
+    if not value: value = element.text or ''	# if no student input yet, then use the default input given by the problem
     context = {'id':eid, 'value':value, 'state':status, 'count':count, 'size': size, 'msg':msg,
                'mode':mode, 'linenumbers':linenumbers,
-               'rows':rows, 'cols':cols,
+               'rows': rows, 'cols': cols, 'height': height,
                'hidden' : hidden,
                }
     html = render_template("textbox.html", context)

common/lib/capa/templates/textbox.html

@@ -42,6 +42,9 @@
     });
   </script>
   <style type="text/css">
+    .CodeMirror-scroll {
+	height: ${height}px;
+    }
     .CodeMirror {border-style: solid;
       border-width: 1px;}
   </style>