diff --git a/ui.c b/ui.c
index 3017758..34b6f7d 100644
--- a/ui.c
+++ b/ui.c
@@ -843,7 +843,7 @@ static void keyCtrl(wchar_t ch) {
 
 static void keyStyle(wchar_t ch) {
 	size_t id = windows.active->id;
-	switch (iswcntrl(ch) ? ch ^ L'@' : towupper(ch)) {
+	switch (iswcntrl(ch) ? ch ^ L'@' : (wchar_t)towupper(ch)) {
 		break; case L'B': edit(id, EditInsert, B);
 		break; case L'C': edit(id, EditInsert, C);
 		break; case L'I': edit(id, EditInsert, I);