settings_ui: Add fallback for `agent_ui_font_size` (#39782)

Finn Evers created

Closes https://github.com/zed-industries/zed/issues/39775

Release Notes:

- N/A

Change summary

crates/settings_ui/src/page_data.rs | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

Detailed changes

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,