diff --git a/niri-config/src/debug.rs b/niri-config/src/debug.rs
index bc09946c..82bfe875 100644
--- a/niri-config/src/debug.rs
+++ b/niri-config/src/debug.rs
@@ -1,45 +1,97 @@
 use std::path::PathBuf;
 
-#[derive(knuffel::Decode, Debug, Default, PartialEq)]
+use crate::utils::{Flag, MergeWith};
+
+#[derive(Debug, Default, PartialEq)]
 pub struct Debug {
+    pub preview_render: Option<PreviewRender>,
+    pub dbus_interfaces_in_non_session_instances: bool,
+    pub wait_for_frame_completion_before_queueing: bool,
+    pub enable_overlay_planes: bool,
+    pub disable_cursor_plane: bool,
+    pub disable_direct_scanout: bool,
+    pub keep_max_bpc_unchanged: bool,
+    pub restrict_primary_scanout_to_matching_format: bool,
+    pub render_drm_device: Option<PathBuf>,
+    pub force_pipewire_invalid_modifier: bool,
+    pub emulate_zero_presentation_time: bool,
+    pub disable_resize_throttling: bool,
+    pub disable_transactions: bool,
+    pub keep_laptop_panel_on_when_lid_is_closed: bool,
+    pub disable_monitor_names: bool,
+    pub strict_new_window_focus_policy: bool,
+    pub honor_xdg_activation_with_invalid_serial: bool,
+    pub deactivate_unfocused_windows: bool,
+    pub skip_cursor_only_updates_during_vrr: bool,
+}
+
+#[derive(knuffel::Decode, Debug, Default, PartialEq)]
+pub struct DebugPart {
     #[knuffel(child, unwrap(argument))]
     pub preview_render: Option<PreviewRender>,
     #[knuffel(child)]
-    pub dbus_interfaces_in_non_session_instances: bool,
+    pub dbus_interfaces_in_non_session_instances: Option<Flag>,
     #[knuffel(child)]
-    pub wait_for_frame_completion_before_queueing: bool,
+    pub wait_for_frame_completion_before_queueing: Option<Flag>,
     #[knuffel(child)]
-    pub enable_overlay_planes: bool,
+    pub enable_overlay_planes: Option<Flag>,
     #[knuffel(child)]
-    pub disable_cursor_plane: bool,
+    pub disable_cursor_plane: Option<Flag>,
     #[knuffel(child)]
-    pub disable_direct_scanout: bool,
+    pub disable_direct_scanout: Option<Flag>,
     #[knuffel(child)]
-    pub keep_max_bpc_unchanged: bool,
+    pub keep_max_bpc_unchanged: Option<Flag>,
     #[knuffel(child)]
-    pub restrict_primary_scanout_to_matching_format: bool,
+    pub restrict_primary_scanout_to_matching_format: Option<Flag>,
     #[knuffel(child, unwrap(argument))]
     pub render_drm_device: Option<PathBuf>,
     #[knuffel(child)]
-    pub force_pipewire_invalid_modifier: bool,
+    pub force_pipewire_invalid_modifier: Option<Flag>,
     #[knuffel(child)]
-    pub emulate_zero_presentation_time: bool,
+    pub emulate_zero_presentation_time: Option<Flag>,
     #[knuffel(child)]
-    pub disable_resize_throttling: bool,
+    pub disable_resize_throttling: Option<Flag>,
     #[knuffel(child)]
-    pub disable_transactions: bool,
+    pub disable_transactions: Option<Flag>,
     #[knuffel(child)]
-    pub keep_laptop_panel_on_when_lid_is_closed: bool,
+    pub keep_laptop_panel_on_when_lid_is_closed: Option<Flag>,
     #[knuffel(child)]
-    pub disable_monitor_names: bool,
+    pub disable_monitor_names: Option<Flag>,
     #[knuffel(child)]
-    pub strict_new_window_focus_policy: bool,
+    pub strict_new_window_focus_policy: Option<Flag>,
     #[knuffel(child)]
-    pub honor_xdg_activation_with_invalid_serial: bool,
+    pub honor_xdg_activation_with_invalid_serial: Option<Flag>,
     #[knuffel(child)]
-    pub deactivate_unfocused_windows: bool,
+    pub deactivate_unfocused_windows: Option<Flag>,
     #[knuffel(child)]
-    pub skip_cursor_only_updates_during_vrr: bool,
+    pub skip_cursor_only_updates_during_vrr: Option<Flag>,
+}
+
+impl MergeWith<DebugPart> for Debug {
+    fn merge_with(&mut self, part: &DebugPart) {
+        merge!(
+            (self, part),
+            dbus_interfaces_in_non_session_instances,
+            wait_for_frame_completion_before_queueing,
+            enable_overlay_planes,
+            disable_cursor_plane,
+            disable_direct_scanout,
+            keep_max_bpc_unchanged,
+            restrict_primary_scanout_to_matching_format,
+            force_pipewire_invalid_modifier,
+            emulate_zero_presentation_time,
+            disable_resize_throttling,
+            disable_transactions,
+            keep_laptop_panel_on_when_lid_is_closed,
+            disable_monitor_names,
+            strict_new_window_focus_policy,
+            honor_xdg_activation_with_invalid_serial,
+            deactivate_unfocused_windows,
+            skip_cursor_only_updates_during_vrr,
+        );
+
+        merge_clone_opt!((self, part), preview_render, render_drm_device);
+    }
 }
 
 #[derive(knuffel::DecodeScalar, Debug, Clone, Copy, PartialEq, Eq)]
diff --git a/niri-config/src/lib.rs b/niri-config/src/lib.rs
index 44b22a18..009d484a 100644
--- a/niri-config/src/lib.rs
+++ b/niri-config/src/lib.rs
@@ -196,7 +196,7 @@ where
                 "overview" => m_replace!(overview),
                 "xwayland-satellite" => m_replace!(xwayland_satellite),
                 "switch-events" => m_merge!(switch_events),
-                "debug" => m_replace!(debug),
+                "debug" => m_merge!(debug),
 
                 // Multipart sections.
                 "output" => {