diff --git a/radio/src/thirdparty/libopenui/src/textedit.cpp b/radio/src/thirdparty/libopenui/src/textedit.cpp
index a3f8a1ecd..18c65c649 100644
--- a/radio/src/thirdparty/libopenui/src/textedit.cpp
+++ b/radio/src/thirdparty/libopenui/src/textedit.cpp
@@ -155,11 +155,14 @@ void TextEdit::onEvent(event_t event)
 
       case EVT_KEY_LONG(KEY_LEFT):
       case EVT_KEY_LONG(KEY_RIGHT):
-        if (v >= -26 && v <= 26) {
-          v = -v; // toggle case
-          if (event == EVT_KEY_LONG(KEY_LEFT)) {
-            killEvents(KEY_LEFT);
-          }
+        if (v >= 'A' && v <= 'Z') {
+          v += 32; // tolower
+        }
+        else if (v >= 'a' && v <= 'z') {
+          v -= 32; // toupper
+        }
+        if (event == EVT_KEY_LONG(KEY_LEFT)) {
+          killEvents(KEY_LEFT);
         }
         break;
     }