Oops, xxp was going to (x) xp :-( now ( ) xxp :-)

common/lib/xmodule/xmodule/js/spec/problem/edit_spec.coffee

@@ -11,8 +11,8 @@ describe 'MarkdownEditingDescriptor', ->
       revisedSelection = MarkdownEditingDescriptor.insertMultipleChoice('a\nx b\nc\nx \nd\n x e')
       expect(revisedSelection).toEqual('( ) a\n(x) b\n( ) c\n( ) x \n( ) d\n(x) e\n')
     it 'recognizes x as a selection if it is first non whitespace and has whitespace with other non-whitespace', ->
-      revisedSelection = MarkdownEditingDescriptor.insertMultipleChoice(' x correct\n x \nex post facto\nb x c\nx c')
-      expect(revisedSelection).toEqual('(x) correct\n( )  x \n( ) ex post facto\n( ) b x c\n(x) c\n')
+      revisedSelection = MarkdownEditingDescriptor.insertMultipleChoice(' x correct\n x \nex post facto\nb x c\nx c\nxxp')
+      expect(revisedSelection).toEqual('(x) correct\n( )  x \n( ) ex post facto\n( ) b x c\n(x) c\n( ) xxp\n')
     it 'removes multiple newlines but not last one', ->
       revisedSelection = MarkdownEditingDescriptor.insertMultipleChoice('a\nx b\n\n\nc\n')
       expect(revisedSelection).toEqual('( ) a\n(x) b\n( ) c\n')

common/lib/xmodule/xmodule/js/src/problem/edit.coffee

@@ -138,9 +138,9 @@ class @MarkdownEditingDescriptor extends XModule.Descriptor
       for line in lines
         revisedLines += choiceStart
         # a stand alone x before other text implies that this option is "correct"
-        if /^\s*x\s*(\S)/i.test(line)
+        if /^\s*x\s+(\S)/i.test(line)
           # Remove the x and any initial whitespace as long as there's more text on the line
-          line = line.replace(/^\s*x\s*(\S)/i, '$1')
+          line = line.replace(/^\s*x\s+(\S)/i, '$1')
           revisedLines += 'x'
         else
           revisedLines += ' '