diff --git a/crates/settings_ui/src/page_data.rs b/crates/settings_ui/src/page_data.rs
index 330de12f32002970b9b46f9cb1098f7295e8dae3..e094992ad815522ddb86ae1de127dbcfaa9ebf1b 100644
--- a/crates/settings_ui/src/page_data.rs
+++ b/crates/settings_ui/src/page_data.rs
@@ -299,7 +299,13 @@ pub(crate) fn settings_data() -> Vec<SettingsPage> {
                     title: "Agent Panel UI Font Size",
                     description: "Font size for agent response text in the agent panel. Falls back to the regular UI font size.",
                     field: Box::new(SettingField {
-                        pick: |settings_content| &settings_content.theme.agent_ui_font_size,
+                        pick: |settings_content| {
+                            if settings_content.theme.agent_ui_font_size.is_some() {
+                                &settings_content.theme.agent_ui_font_size
+                            } else {
+                                &settings_content.theme.ui_font_size
+                            }
+                        },
                         pick_mut: |settings_content| &mut settings_content.theme.agent_ui_font_size,
                     }),
                     metadata: None,