[CORD-1792] modifier key detection

Change-Id: I35b5e59044474afee23513a7baf3b157517f3e75
(cherry picked from commit 3e2f13b477486e7875fed54bfc2655a629892b49)
diff --git a/src/app/core/services/keyboard-shortcut.ts b/src/app/core/services/keyboard-shortcut.ts
index b8678f7..9b98b45 100644
--- a/src/app/core/services/keyboard-shortcut.ts
+++ b/src/app/core/services/keyboard-shortcut.ts
@@ -106,8 +106,8 @@
         return;
       }
 
-      if (this.allowedModifiers.indexOf(e.key) > -1) {
-        this.addActiveModifierKey(e.key);
+      if (this.allowedModifiers.indexOf(e.key.toLowerCase()) > -1) {
+        this.addActiveModifierKey(e.key.toLowerCase());
         return;
       }
 
@@ -126,8 +126,8 @@
     });
 
     $('body').on('keyup', (e) => {
-      if (this.allowedModifiers.indexOf(e.key) > -1) {
-        this.removeActiveModifierKey(e.key);
+      if (this.allowedModifiers.indexOf(e.key.toLowerCase()) > -1) {
+        this.removeActiveModifierKey(e.key.toLowerCase());
         return;
       }
     });