diff --git a/firmware/common/ui_widget.hpp b/firmware/common/ui_widget.hpp
index 11ce4e165..7ab54597a 100644
--- a/firmware/common/ui_widget.hpp
+++ b/firmware/common/ui_widget.hpp
@@ -40,9 +40,11 @@ namespace ui {
 
 extern void dirty_event();
 
-std::string to_string_dec_uint(const uint32_t n, const int32_t l, const char fill = 0);
-std::string to_string_dec_int(const int32_t n, const int32_t l, const char fill = 0);
-std::string to_string_hex(const uint32_t n, const int32_t l);
+// TODO: Move these somewhere else!
+// TODO: Allow l=0 to not fill/justify? Already using this way in ui_spectrum.hpp...
+std::string to_string_dec_uint(const uint32_t n, const int32_t l = 0, const char fill = 0);
+std::string to_string_dec_int(const int32_t n, const int32_t l = 0, const char fill = 0);
+std::string to_string_hex(const uint32_t n, const int32_t l = 0);
 
 struct Context {
 	FocusManager focus_manager;