diff --git a/src/config.py b/src/config.py
index 48eb522f4eef9d832e11252d803569f9721ae56f..caa0cc5888deb903c067b8450bb75da778720145 100644
--- a/src/config.py
+++ b/src/config.py
@@ -4154,7 +4154,8 @@ class ManageSoundsWindow:
     def __init__(self):
         self.xml = gtkgui_helpers.get_gtk_builder('manage_sounds_window.ui')
         self.window = self.xml.get_object('manage_sounds_window')
-
+        self.window.set_transient_for(
+            gajim.interface.instances['preferences'].window)
         # sounds treeview
         self.sound_tree = self.xml.get_object('sounds_treeview')
 
diff --git a/src/gajim_themes_window.py b/src/gajim_themes_window.py
index 2b923590fe22297d034e640624542c225d5a35e5..56c85b04e575db42419e40c91e8ca8a7334e1c37 100644
--- a/src/gajim_themes_window.py
+++ b/src/gajim_themes_window.py
@@ -34,7 +34,8 @@ class GajimThemesWindow:
     def __init__(self):
         self.xml = gtkgui_helpers.get_gtk_builder('gajim_themes_window.ui')
         self.window = self.xml.get_object('gajim_themes_window')
-        self.window.set_transient_for(gajim.interface.roster.window)
+        self.window.set_transient_for(gajim.interface.instances[
+            'preferences'].window)
 
         self.options = ['account', 'group', 'contact', 'banner']
         self.options_combobox = self.xml.get_object('options_combobox')