diff --git a/hippolyzer/apps/proxy_gui.py b/hippolyzer/apps/proxy_gui.py
index 3d1c132..1301e5a 100644
--- a/hippolyzer/apps/proxy_gui.py
+++ b/hippolyzer/apps/proxy_gui.py
@@ -34,7 +34,7 @@ from hippolyzer.lib.base.message.message_formatting import (
     SpannedString,
 )
 from hippolyzer.lib.base.message.msgtypes import MsgType
-from hippolyzer.lib.base.message.template_dict import TemplateDictionary
+from hippolyzer.lib.base.message.template_dict import DEFAULT_TEMPLATE_DICT
 from hippolyzer.lib.base.ui_helpers import loadUi
 import hippolyzer.lib.base.serialization as se
 from hippolyzer.lib.base.network.transport import Direction, SocketUDPTransport
@@ -446,7 +446,7 @@ class MessageBuilderWindow(QtWidgets.QMainWindow):
     def __init__(self, parent, session_manager):
         super().__init__(parent=parent)
         loadUi(MESSAGE_BUILDER_UI_PATH, self)
-        self.templateDict = TemplateDictionary()
+        self.templateDict = DEFAULT_TEMPLATE_DICT
         self.llsdSerializer = LLSDMessageSerializer()
         self.sessionManager: SessionManager = session_manager
         self.regionModel = RegionListModel(self, self.sessionManager)
diff --git a/hippolyzer/lib/base/message/llsd_msg_serializer.py b/hippolyzer/lib/base/message/llsd_msg_serializer.py
index 1120e64..f54e0d6 100644
--- a/hippolyzer/lib/base/message/llsd_msg_serializer.py
+++ b/hippolyzer/lib/base/message/llsd_msg_serializer.py
@@ -5,14 +5,13 @@ from hippolyzer.lib.base import llsd
 from hippolyzer.lib.base.message.data_packer import LLSDDataPacker
 from hippolyzer.lib.base.message.message import Message
 from hippolyzer.lib.base.message.template import MessageTemplateVariable
-from hippolyzer.lib.base.message.template_dict import TemplateDictionary
-
+from hippolyzer.lib.base.message.template_dict import TemplateDictionary, DEFAULT_TEMPLATE_DICT
 
 VAR_PAIR = Tuple[dict, MessageTemplateVariable]
 
 
 class LLSDMessageSerializer:
-    DEFAULT_TEMPLATE = TemplateDictionary()
+    DEFAULT_TEMPLATE = DEFAULT_TEMPLATE_DICT
 
     def __init__(self, message_template=None, message_cls: Type[Message] = Message):
         if message_template is not None:
diff --git a/hippolyzer/lib/base/message/template_dict.py b/hippolyzer/lib/base/message/template_dict.py
index a67ad30..16d1840 100644
--- a/hippolyzer/lib/base/message/template_dict.py
+++ b/hippolyzer/lib/base/message/template_dict.py
@@ -27,25 +27,35 @@ from .template import MessageTemplate
 from .template_parser import MessageTemplateParser
 
 
+DEFAULT_PARSER = MessageTemplateParser(msg_tmpl)
+
+
 class TemplateDictionary:
     """the dictionary with all known templates"""
 
     def __init__(self, template_list=None, message_template=None):
         if template_list is None:
             if message_template is None:
-                parser = MessageTemplateParser(msg_tmpl)
+                parser = DEFAULT_PARSER
             else:
                 parser = MessageTemplateParser(message_template)
             template_list = parser.message_templates
 
-        self.template_list: typing.List[MessageTemplate] = template_list
-
+        self.template_list: typing.List[MessageTemplate] = []
         # maps name to template
         self.message_templates = {}
 
         # maps (freq,num) to template
         self.message_dict = {}
 
+        self.load_templates(template_list)
+
+    def load_templates(self, template_list):
+        self.template_list.clear()
+        self.template_list.extend(template_list)
+        self.message_templates.clear()
+        self.message_dict.clear()
+
         self.build_dictionaries(template_list)
         self.build_message_ids()
 
@@ -99,3 +109,6 @@ class TemplateDictionary:
 
     def __iter__(self):
         return iter(self.template_list)
+
+
+DEFAULT_TEMPLATE_DICT = TemplateDictionary()
diff --git a/hippolyzer/lib/base/message/udpdeserializer.py b/hippolyzer/lib/base/message/udpdeserializer.py
index 330a17e..01cfd0c 100644
--- a/hippolyzer/lib/base/message/udpdeserializer.py
+++ b/hippolyzer/lib/base/message/udpdeserializer.py
@@ -26,7 +26,7 @@ from logging import getLogger
 from hippolyzer.lib.base.datatypes import JankStringyBytes
 from hippolyzer.lib.base.settings import Settings
 from .template import MessageTemplateVariable
-from .template_dict import TemplateDictionary
+from .template_dict import DEFAULT_TEMPLATE_DICT
 from .msgtypes import MsgType, MsgBlockType, PacketLayout
 from .data_packer import TemplateDataPacker
 from .message import Message, Block
@@ -62,7 +62,7 @@ def _parse_msg_num(reader: se.BufferReader):
 
 
 class UDPMessageDeserializer:
-    DEFAULT_TEMPLATE = TemplateDictionary()
+    DEFAULT_TEMPLATE = DEFAULT_TEMPLATE_DICT
 
     def __init__(self, settings=None):
         self.settings = settings or Settings()
diff --git a/hippolyzer/lib/base/message/udpserializer.py b/hippolyzer/lib/base/message/udpserializer.py
index b85ec21..e5617a0 100644
--- a/hippolyzer/lib/base/message/udpserializer.py
+++ b/hippolyzer/lib/base/message/udpserializer.py
@@ -26,7 +26,7 @@ from .data_packer import TemplateDataPacker
 from .message import Message, MsgBlockList
 from .msgtypes import MsgType, MsgBlockType
 from .template import MessageTemplateVariable, MessageTemplateBlock
-from .template_dict import TemplateDictionary
+from .template_dict import TemplateDictionary, DEFAULT_TEMPLATE_DICT
 from hippolyzer.lib.base import exc
 from hippolyzer.lib.base import serialization as se
 from hippolyzer.lib.base.datatypes import RawBytes
@@ -35,7 +35,7 @@ logger = getLogger('message.udpserializer')
 
 
 class UDPMessageSerializer:
-    DEFAULT_TEMPLATE = TemplateDictionary(None)
+    DEFAULT_TEMPLATE = DEFAULT_TEMPLATE_DICT
 
     def __init__(self, message_template=None):
         if message_template is not None: