diff --git a/bec_widgets/utils/bec_designer.py b/bec_widgets/utils/bec_designer.py
index a1353a3a..e96e1f59 100644
--- a/bec_widgets/utils/bec_designer.py
+++ b/bec_widgets/utils/bec_designer.py
@@ -1,4 +1,8 @@
+import ast
 import importlib.metadata
+import importlib.util
+import inspect
+import itertools
 import json
 import os
 import site
@@ -6,11 +10,14 @@ import sys
 import sysconfig
 from pathlib import Path
 
+from bec_lib.logger import bec_logger
 from bec_qthemes import material_icon
 from qtpy import PYSIDE6
 from qtpy.QtGui import QIcon
+from zmq import PLAIN
 
 from bec_widgets.utils.bec_plugin_helper import user_widget_plugin
+from bec_widgets.utils.bec_widget import BECWidget
 
 if PYSIDE6:
     from PySide6.scripts.pyside_tool import (
@@ -24,6 +31,8 @@ if PYSIDE6:
 
 import bec_widgets
 
+logger = bec_logger.logger
+
 
 def designer_material_icon(icon_name: str) -> QIcon:
     """
@@ -122,14 +131,43 @@ def patch_designer():  # pragma: no cover
     qt_tool_wrapper(ui_tool_binary("designer"), sys.argv[1:])
 
 
-def find_plugin_paths(base_path: Path):
+def _plugin_classes_for_python_file(file: Path):
+    logger.debug(f"getting plugin classes for {file}")
+    if not str(file).endswith(".py"):
+        raise ValueError("Please pass a python file")
+    spec = importlib.util.spec_from_file_location("_temp", file)
+    mod = importlib.util.module_from_spec(spec)
+    sys.modules["_temp"] = mod
+    spec.loader.exec_module(mod)
+
+    plugin_widgets = list(
+        mem[0]
+        for mem in inspect.getmembers(mod, inspect.isclass)
+        if issubclass(mem[1], BECWidget) and hasattr(mem[1], "PLUGIN") and mem[1].PLUGIN is True
+    )
+    logger.debug(f"Found: {plugin_widgets}")
+    return plugin_widgets
+
+
+def _plugin_classes_for_pyproject(path: Path):
+    if not str(path).endswith(".pyproject"):
+        raise ValueError("Please pass the path of the designer pyproject file")
+    with open(path) as pyproject:
+        plugin_filenames = ast.literal_eval(pyproject.read())["files"]
+    plugin_files = (path.parent / file for file in plugin_filenames)
+    return itertools.chain(*(_plugin_classes_for_python_file(f) for f in plugin_files))
+
+
+def find_plugin_paths(base_path: Path) -> dict[str, list[str]]:
     """
-    Recursively find all directories containing a .pyproject file.
+    Recursively find all directories containing a .pyproject file. Returns a dictionary with keys of
+    such paths, and values of the names of the classes contained in them if those classes are
+    desginer plugins.
     """
-    plugin_paths = []
-    for path in base_path.rglob("*.pyproject"):
-        plugin_paths.append(str(path.parent))
-    return plugin_paths
+    return {
+        str(path.parent): list(_plugin_classes_for_pyproject(path))
+        for path in base_path.rglob("*.pyproject")
+    }
 
 
 def set_plugin_environment_variable(plugin_paths):
@@ -146,6 +184,19 @@ def set_plugin_environment_variable(plugin_paths):
     os.environ["PYSIDE_DESIGNER_PLUGINS"] = os.pathsep.join(current_paths)
 
 
+def _extend_plugin_paths(plugin_paths: dict[str, list[str]], plugin_repo_dir: Path):
+    plugin_plugin_paths = find_plugin_paths(plugin_repo_dir)
+    builtin_plugin_names = list(itertools.chain(*plugin_paths.values()))
+    for plugin_file, plugin_classes in plugin_plugin_paths.items():
+        logger.info(f"{plugin_classes} {builtin_plugin_names}")
+        if any(name in builtin_plugin_names for name in plugin_classes):
+            logger.warning(
+                f"Ignoring plugin {plugin_file} because it contains widgets {plugin_classes} which include duplicates of built-in widgets!"
+            )
+        else:
+            plugin_paths[plugin_file] = plugin_classes
+
+
 # Patch the designer function
 def main():  # pragma: no cover
     if not PYSIDE6:
@@ -154,11 +205,12 @@ def main():  # pragma: no cover
     base_dir = Path(os.path.dirname(bec_widgets.__file__)).resolve()
 
     plugin_paths = find_plugin_paths(base_dir)
+
     if (plugin_repo := user_widget_plugin()) and isinstance(plugin_repo.__file__, str):
         plugin_repo_dir = Path(os.path.dirname(plugin_repo.__file__)).resolve()
-        plugin_paths.extend(find_plugin_paths(plugin_repo_dir))
+        _extend_plugin_paths(plugin_paths, plugin_repo_dir)
 
-    set_plugin_environment_variable(plugin_paths)
+    set_plugin_environment_variable(plugin_paths.keys())
 
     patch_designer()