diff --git a/libs/ui/source/edit.cpp b/libs/ui/source/edit.cpp
index 7b43b313..179373f2 100644
--- a/libs/ui/source/edit.cpp
+++ b/libs/ui/source/edit.cpp
@@ -70,14 +70,14 @@ namespace psemek::ui
 			if (begin != end && *begin == '-')
 				++begin;
 
-			return std::all_of(begin, end, [](char c){ return '0' <= c && c <= '9'; });
+			return std::all_of(begin, end, [](char32_t c){ return '0' <= c && c <= '9'; });
 		};
 	}
 
 	edit::validator_type edit::numeric_nonnegative()
 	{
 		return [](std::u32string_view const str) -> bool {
-			return std::all_of(str.begin(), str.end(), [](char c){ return '0' <= c && c <= '9'; });
+			return std::all_of(str.begin(), str.end(), [](char32_t c){ return '0' <= c && c <= '9'; });
 		};
 	}