allow adding combat zone wins even if an entry is selected

MainWindow.xaml.cs

@@ -206,18 +206,42 @@ namespace EliteBGS {
             }
         }
 
-        private void AddCombatZone_Click(object sender, RoutedEventArgs e) {
-            if (entries.SelectedItem == null) {
-                return;
-            }
-
+        /// <summary>
+        /// Gets the currently selected objective, even if a log entry in said objective
+        /// is selected instead. If nothing is selected, returns null.
+        /// </summary>
+        /// <returns></returns>
+        private Objective GetSelectedObjective() {
             var obj = entries.SelectedItem;
 
-            if (obj.GetType() != typeof(Objective)) {
-                return;
+            if (obj == null) {
+                return null;
             }
 
-            Objective objective = obj as Objective;
+            if (obj.GetType() == typeof(Objective)) {
+                return obj as Objective;
+            }
+
+            // Some form of entry perhaps?
+            if (obj.GetType().IsSubclassOf(typeof(LogEntry))) {
+                LogEntry entry = obj as LogEntry;
+                Objective objective = entries.Items
+                    .OfType<Objective>()
+                    .First(x => x.LogEntries.Contains(entry))
+                    ;
+
+                return objective;
+            }
+
+            return null;
+        }
+
+        private void AddCombatZone_Click(object sender, RoutedEventArgs e) {
+            Objective objective = GetSelectedObjective();
+
+            if (objective == null) {
+                return;
+            }
 
             CombatZoneDialog dialog = new CombatZoneDialog() { Owner = this };