diff --git a/include/euiTextBoxEx.h b/include/euiTextBoxEx.h
new file mode 100644
index 0000000..69f383b
--- /dev/null
+++ b/include/euiTextBoxEx.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <basis/seadTypes.h>
+#include <nn/ui2d/Pane.h>
+
+namespace eui {
+class TextBoxEx {
+public:
+    u8 _0[0x11c];
+    u8 mDirtyFlags;
+};
+}  // namespace eui
+
+namespace nn::ui2d {
+template <typename T, typename U>
+T DynamicCast(U* pane);
+
+template <>
+eui::TextBoxEx* DynamicCast<eui::TextBoxEx*, nn::ui2d::Pane>(nn::ui2d::Pane* pane);
+}  // namespace nn::ui2d
\ No newline at end of file