diff --git a/slic/gui/persist.py b/slic/gui/persist.py
index c02aa1f4..5ab64d2d 100644
--- a/slic/gui/persist.py
+++ b/slic/gui/persist.py
@@ -3,13 +3,6 @@ from slic.gui import widgets as ws
 from slic.gui.special import ValueEntry
 
 
-PERSISTABLE_WIDGETS = (
-    ws.MathEntry,
-    ws.FilenameEntry,
-    ValueEntry
-)
-
-
 def store(*args):
     p = Persistence(*args)
     p.store()
@@ -55,7 +48,7 @@ class Persistence:
 
 
     def get_good_children(self):
-        return list(c for c in recurse(self.managed) if isinstance(c, PERSISTABLE_WIDGETS))
+        return list(c for c in recurse(self.managed) if isinstance(c, ws.PersistableWidget))
 
 
 
diff --git a/slic/gui/special.py b/slic/gui/special.py
index 3faf1581..43d59dde 100644
--- a/slic/gui/special.py
+++ b/slic/gui/special.py
@@ -2,13 +2,13 @@ import numpy as np
 import wx
 
 from .daqpanels import AdjustableComboBox, ETADisplay, correct_n_pulses, run, post_event
-from .widgets import LabeledMathEntry, LabeledEntry, LabeledFilenameEntry, TwoButtons, make_filled_hbox, make_filled_vbox, STRETCH, EXPANDING
+from .widgets import LabeledMathEntry, LabeledEntry, LabeledFilenameEntry, TwoButtons, make_filled_hbox, make_filled_vbox, STRETCH, EXPANDING, PersistableWidget
 
 from slic.utils import nice_arange, readable_seconds
 from slic.utils.reprate import get_pvname_reprate
 
 
-class ValueEntry(wx.TextCtrl):
+class ValueEntry(wx.TextCtrl, PersistableWidget):
     pass
 
 
diff --git a/slic/gui/widgets.py b/slic/gui/widgets.py
index 15d415da..d8708cb6 100644
--- a/slic/gui/widgets.py
+++ b/slic/gui/widgets.py
@@ -7,6 +7,12 @@ from .fname import increase, decrease
 from .helper import exception_to_warning
 
 
+
+class PersistableWidget:
+    pass
+
+
+
 WX_DEFAULT_RESIZABLE_DIALOG_STYLE = wx.DEFAULT_DIALOG_STYLE|wx.RESIZE_BORDER|wx.MINIMIZE_BOX|wx.MAXIMIZE_BOX
 
 
@@ -288,7 +294,7 @@ class LabeledMathEntry(wx.BoxSizer): #TODO: largely copy of LabeledEntry
 
 
 
-class MathEntry(wx.TextCtrl):
+class MathEntry(wx.TextCtrl, PersistableWidget):
 
     def __init__(self, *args, **kwargs):
         if "style" in kwargs:
@@ -375,7 +381,7 @@ class LabeledFilenameEntry(wx.BoxSizer): #TODO: largely copy of LabeledEntry
 
 
 
-class FilenameEntry(wx.TextCtrl):
+class FilenameEntry(wx.TextCtrl, PersistableWidget):
 
     def __init__(self, *args, **kwargs):
         if "style" in kwargs: