diff --git a/src/config.py b/src/config.py
index cc9ca9c52..d648ed2cc 100644
--- a/src/config.py
+++ b/src/config.py
@@ -4152,7 +4152,8 @@ 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 03d295050..5f2d7d3d9 100644
--- a/src/gajim_themes_window.py
+++ b/src/gajim_themes_window.py
@@ -35,7 +35,8 @@ 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')