diff --git a/src/Main_Class.ahk b/src/Main_Class.ahk
index b157d71..ff275d0 100644
--- a/src/Main_Class.ahk
+++ b/src/Main_Class.ahk
@@ -411,9 +411,9 @@
     
     ; Low-level keyboard hook callback
     LowLevelKeyboardProc(nCode, wParam, lParam) {
-        static WM_KEYDOWN := 0x100, WM_SYSKEYDOWN := 0x104
+        static WM_KEYUP := 0x0101, WM_SYSKEYUP := 0x0105
         
-        if (nCode >= 0 && (wParam = WM_KEYDOWN || wParam = WM_SYSKEYDOWN)) {
+        if (nCode >= 0 && (wParam = WM_KEYUP || wParam = WM_SYSKEYUP)) {
             vkCode := NumGet(lParam, 0, "UInt")
             ; Ignore modifier keys themselves
             if (vkCode = 0x10 || vkCode = 0x11 || vkCode = 0x12