diff --git a/lib/tfw/components/source_code_event_handler.py b/lib/tfw/components/source_code_event_handler.py
index c7269d0..b780c98 100644
--- a/lib/tfw/components/source_code_event_handler.py
+++ b/lib/tfw/components/source_code_event_handler.py
@@ -1,4 +1,4 @@
-from os.path import isfile, join, relpath
+from os.path import isfile, join, relpath, exists, isdir
 from glob import glob
 
 from tfw.event_handler_base import TriggerlessEventHandler
@@ -11,9 +11,20 @@ log = logging.getLogger(__name__)
 class FileManager:
     def __init__(self, working_directory, selected_file=None):
         self.exclude = ['__pycache__']
-        self._workdir = working_directory
+        self._workdir = None
+        self.workdir = working_directory
         self.filename = selected_file or self.files[0]
 
+    @property
+    def workdir(self):
+        return self._workdir
+
+    @workdir.setter
+    def workdir(self, directory):
+        if not exists(directory) or not isdir(directory):
+            raise EnvironmentError('"{}" is not a directory!'.format(directory))
+        self._workdir = directory
+
     def select_file(self, filename):
         if not filename in self.files:
            raise EnvironmentError('No such file in workdir!')