7 files changed, 24 insertions, 15 deletions
diff --git a/grc/core/Block.py b/grc/core/Block.py
index c2c7d4e821..6708986939 100644
--- a/grc/core/Block.py
+++ b/grc/core/Block.py
@@ -21,7 +21,6 @@ import collections
 import itertools
 
 from Cheetah.Template import Template
-from UserDict import UserDict
 
 from .utils import epy_block_io, odict
 from . Constants import (
@@ -442,11 +441,10 @@ class Block(Element):
                 self._params.remove(param)
 
         for key, value in blk_io.params:
-            if key in params:
+            try:
                 param = params[key]
-                if not param.value_is_default():
-                    param.set_value(value)
-            else:
+                param.set_default(value)
+            except KeyError:  # need to make a new param
                 name = key.replace('_', ' ').title()
                 n = odict(dict(name=name, key=key, type='raw', value=value))
                 param = platform.Param(block=self, n=n)
diff --git a/grc/core/Element.py b/grc/core/Element.py
index c999d6704f..b96edb0a72 100644
--- a/grc/core/Element.py
+++ b/grc/core/Element.py
@@ -41,9 +41,9 @@ class Element(object):
         Is this element valid?
 
         Returns:
-            true when the element is enabled and has no error messages
+            true when the element is enabled and has no error messages or is bypassed
         """
-        return not self.get_error_messages() or not self.get_enabled()
+        return (not self.get_error_messages() or not self.get_enabled()) or self.get_bypassed()
 
     def add_error_message(self, msg):
         """
@@ -57,14 +57,14 @@ class Element(object):
     def get_error_messages(self):
         """
         Get the list of error messages from this element and all of its children.
-        Do not include the error messages from disabled children.
+        Do not include the error messages from disabled or bypassed children.
         Cleverly indent the children error messages for printing purposes.
 
         Returns:
             a list of error message strings
         """
         error_messages = list(self._error_messages)  # Make a copy
-        for child in filter(lambda c: c.get_enabled(), self.get_children()):
+        for child in filter(lambda c: c.get_enabled() and not c.get_bypassed(), self.get_children()):
             for msg in child.get_error_messages():
                 error_messages.append("{}:\n\t{}".format(child, msg.replace("\n", "\n\t")))
         return error_messages
@@ -80,6 +80,9 @@ class Element(object):
     def get_enabled(self):
         return True
 
+    def get_bypassed(self):
+        return False
+
     ##############################################
     # Tree-like API
     ##############################################
diff --git a/grc/core/FlowGraph.py b/grc/core/FlowGraph.py
index 177d16baa9..313af3107a 100644
--- a/grc/core/FlowGraph.py
+++ b/grc/core/FlowGraph.py
@@ -424,7 +424,7 @@ class FlowGraph(Element):
 
             block.import_data(block_n)
 
-        self.rewrite()
+        self.rewrite()  # evaluate stuff like nports before adding connections
 
         # build the connections
         def verify_and_get_port(key, block, dir):
diff --git a/grc/core/Param.py b/grc/core/Param.py
index 04c4967f53..d155800c43 100644
--- a/grc/core/Param.py
+++ b/grc/core/Param.py
@@ -683,8 +683,10 @@ class Param(Element):
         # Must be a string
         self._value = str(value)
 
-    def value_is_default(self):
-        return self._default == self._value
+    def set_default(self, value):
+        if self._default == self._value:
+            self.set_value(value)
+        self._default = str(value)
 
     def get_type(self):
         return self.get_parent().resolve_dependencies(self._type)
diff --git a/grc/core/ParseXML.py b/grc/core/ParseXML.py
index 987fa2a13d..c9f6541ee7 100644
--- a/grc/core/ParseXML.py
+++ b/grc/core/ParseXML.py
@@ -22,6 +22,7 @@ from lxml import etree
 from .utils import odict
 
 xml_failures = {}
+etree.set_default_parser(etree.XMLParser(remove_comments=True))
 
 
 class XMLSyntaxError(Exception):
diff --git a/grc/core/Port.py b/grc/core/Port.py
index 4964a94c2b..6a8f484082 100644
--- a/grc/core/Port.py
+++ b/grc/core/Port.py
@@ -129,7 +129,7 @@ class Port(Element):
         # Grab the data
         self._name = n['name']
         self._key = n['key']
-        self._type = n['type']
+        self._type = n['type'] or ''
         self._domain = n['domain']
         self._hide = n.find('hide') or ''
         self._dir = dir
diff --git a/grc/core/generator/flow_graph.tmpl b/grc/core/generator/flow_graph.tmpl
index bd8025b676..ecdb89390e 100644
--- a/grc/core/generator/flow_graph.tmpl
+++ b/grc/core/generator/flow_graph.tmpl
@@ -274,8 +274,8 @@ gr.io_signaturev($(len($io_sigs)), $(len($io_sigs)), [$(', '.join($size_strs))])
         self.settings = Qt.QSettings("GNU Radio", "$class_name")
         self.settings.setValue("geometry", self.saveGeometry())
         event.accept()
-
     #if $flow_graph.get_option('qt_qss_theme')
+
     def setStyleSheetFromFile(self, filename):
         try:
             if not os.path.exists(filename):
@@ -336,7 +336,12 @@ $short_id#slurp
 
 
 def argument_parser():
-    parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
+    #set $desc_args = 'usage="%prog: [options]", option_class=eng_option'
+    #if $flow_graph.get_option('description')
+        #set $desc_args += ', description=description'
+    description = $repr($flow_graph.get_option('description'))
+    #end if
+    parser = OptionParser($desc_args)
     #for $param in $parameters
         #set $type = $param.get_param('type').get_value()
         #if $type