diff --git a/codex-rs/tui/src/custom_terminal.rs b/codex-rs/tui/src/custom_terminal.rs
index d7957f8ecf..c2a6f05895 100644
--- a/codex-rs/tui/src/custom_terminal.rs
+++ b/codex-rs/tui/src/custom_terminal.rs
@@ -730,13 +730,13 @@ where
 /// The `ModifierDiff` struct is used to calculate the difference between two `Modifier`
 /// values. This is useful when updating the terminal display, as it allows for more
 /// efficient updates by only sending the necessary changes.
-struct ModifierDiff {
+pub(crate) struct ModifierDiff {
     pub from: Modifier,
     pub to: Modifier,
 }
 
 impl ModifierDiff {
-    fn queue<W: io::Write>(self, w: &mut W) -> io::Result<()> {
+    pub(crate) fn queue<W: io::Write>(self, w: &mut W) -> io::Result<()> {
         use crossterm::style::Attribute as CAttribute;
         let removed = self.from - self.to;
         if removed.contains(Modifier::REVERSED) {
diff --git a/codex-rs/tui/src/insert_history.rs b/codex-rs/tui/src/insert_history.rs
index d07d6cbe3a..afa649f70a 100644
--- a/codex-rs/tui/src/insert_history.rs
+++ b/codex-rs/tui/src/insert_history.rs
@@ -8,6 +8,7 @@ use std::fmt;
 use std::io;
 use std::io::Write;
 
+use crate::custom_terminal::ModifierDiff;
 use crate::render::line_utils::line_to_static;
 use crate::terminal_hyperlinks::HyperlinkLine;
 use crate::terminal_hyperlinks::decorate_spans;
@@ -381,73 +382,6 @@ impl Command for ResetScrollRegion {
     }
 }
 
-struct ModifierDiff {
-    pub from: Modifier,
-    pub to: Modifier,
-}
-
-impl ModifierDiff {
-    fn queue<W>(self, mut w: W) -> io::Result<()>
-    where
-        W: io::Write,
-    {
-        use crossterm::style::Attribute as CAttribute;
-        let removed = self.from - self.to;
-        if removed.contains(Modifier::REVERSED) {
-            queue!(w, SetAttribute(CAttribute::NoReverse))?;
-        }
-        if removed.contains(Modifier::BOLD) {
-            queue!(w, SetAttribute(CAttribute::NormalIntensity))?;
-            if self.to.contains(Modifier::DIM) {
-                queue!(w, SetAttribute(CAttribute::Dim))?;
-            }
-        }
-        if removed.contains(Modifier::ITALIC) {
-            queue!(w, SetAttribute(CAttribute::NoItalic))?;
-        }
-        if removed.contains(Modifier::UNDERLINED) {
-            queue!(w, SetAttribute(CAttribute::NoUnderline))?;
-        }
-        if removed.contains(Modifier::DIM) {
-            queue!(w, SetAttribute(CAttribute::NormalIntensity))?;
-        }
-        if removed.contains(Modifier::CROSSED_OUT) {
-            queue!(w, SetAttribute(CAttribute::NotCrossedOut))?;
-        }
-        if removed.contains(Modifier::SLOW_BLINK) || removed.contains(Modifier::RAPID_BLINK) {
-            queue!(w, SetAttribute(CAttribute::NoBlink))?;
-        }
-
-        let added = self.to - self.from;
-        if added.contains(Modifier::REVERSED) {
-            queue!(w, SetAttribute(CAttribute::Reverse))?;
-        }
-        if added.contains(Modifier::BOLD) {
-            queue!(w, SetAttribute(CAttribute::Bold))?;
-        }
-        if added.contains(Modifier::ITALIC) {
-            queue!(w, SetAttribute(CAttribute::Italic))?;
-        }
-        if added.contains(Modifier::UNDERLINED) {
-            queue!(w, SetAttribute(CAttribute::Underlined))?;
-        }
-        if added.contains(Modifier::DIM) {
-            queue!(w, SetAttribute(CAttribute::Dim))?;
-        }
-        if added.contains(Modifier::CROSSED_OUT) {
-            queue!(w, SetAttribute(CAttribute::CrossedOut))?;
-        }
-        if added.contains(Modifier::SLOW_BLINK) {
-            queue!(w, SetAttribute(CAttribute::SlowBlink))?;
-        }
-        if added.contains(Modifier::RAPID_BLINK) {
-            queue!(w, SetAttribute(CAttribute::RapidBlink))?;
-        }
-
-        Ok(())
-    }
-}
-
 fn write_spans<'a, I>(mut writer: &mut impl Write, content: I) -> io::Result<()>
 where
     I: IntoIterator<Item = &'a Span<'a>>,
diff --git a/codex-rs/tui/src/terminal_palette.rs b/codex-rs/tui/src/terminal_palette.rs
index 7ff9b968f9..8364c6b7d7 100644
--- a/codex-rs/tui/src/terminal_palette.rs
+++ b/codex-rs/tui/src/terminal_palette.rs
@@ -142,7 +142,7 @@ pub(crate) fn set_default_colors_from_startup_probe(
     imp::set_default_colors_from_startup_probe(colors);
 }
 
-#[cfg(all(unix, not(test)))]
+#[cfg(any(all(unix, not(test)), windows))]
 mod imp {
     use super::DefaultColors;
     use std::sync::Mutex;
@@ -211,70 +211,6 @@ mod imp {
     }
 }
 
-#[cfg(windows)]
-mod imp {
-    use super::DefaultColors;
-    use std::sync::Mutex;
-    use std::sync::OnceLock;
-
-    struct Cache<T> {
-        attempted: bool,
-        value: Option<T>,
-    }
-
-    impl<T> Default for Cache<T> {
-        fn default() -> Self {
-            Self {
-                attempted: false,
-                value: None,
-            }
-        }
-    }
-
-    impl<T: Copy> Cache<T> {
-        fn get_or_init_with(&mut self, mut init: impl FnMut() -> Option<T>) -> Option<T> {
-            if !self.attempted {
-                self.value = init();
-                self.attempted = true;
-            }
-            self.value
-        }
-    }
-
-    fn default_colors_cache() -> &'static Mutex<Cache<DefaultColors>> {
-        static CACHE: OnceLock<Mutex<Cache<DefaultColors>>> = OnceLock::new();
-        CACHE.get_or_init(|| Mutex::new(Cache::default()))
-    }
-
-    pub(super) fn default_colors() -> Option<DefaultColors> {
-        let cache = default_colors_cache();
-        let mut cache = cache.lock().ok()?;
-        cache.get_or_init_with(query_default_colors)
-    }
-
-    pub(super) fn set_default_colors_from_startup_probe(
-        colors: Option<crate::terminal_probe::DefaultColors>,
-    ) {
-        if let Ok(mut cache) = default_colors_cache().lock() {
-            cache.value = colors.map(|colors| DefaultColors {
-                fg: colors.fg,
-                bg: colors.bg,
-            });
-            cache.attempted = true;
-        }
-    }
-
-    fn query_default_colors() -> Option<DefaultColors> {
-        crate::terminal_probe::default_colors(crate::terminal_probe::DEFAULT_TIMEOUT)
-            .ok()
-            .flatten()
-            .map(|colors| DefaultColors {
-                fg: colors.fg,
-                bg: colors.bg,
-            })
-    }
-}
-
 #[cfg(not(any(all(unix, not(test)), windows)))]
 mod imp {
     use super::DefaultColors;