/// <summary>
        /// Pre: n/a
        /// Post: n/a
        /// Description: Updates the filter
        /// </summary>
        private void UpdateFilter()
        {
            // Code only executes if filter is active
            if (filterActive)
            {
                // Creates new dictionary of filtered indexes
                filteredIndex = new Dictionary<int, int>();

                // Filters the inventory with user's input
                List<int> filteredList = inventory.FilterItems((string)filterTypeComboBox.SelectedItem, filterTitleTxt.Text, (string)filterPlatformComboBox.SelectedItem);

                // Clears the list box
                itemListBox.Items.Clear();

                // Loops through each filtered item
                for (int i = 0; i < filteredList.Count; ++i)
                {
                    // Adds each filtered item to the list box
                    itemListBox.Items.Add(inventory.items[filteredList[i]].Display());

                    // Adds the index to the dictionary of filtered indexes
                    filteredIndex.Add(i, filteredList[i]);
                }

                // Resets selected index to 0, unless there are 0 items (prevents crashing)
                if (itemListBox.Items.Count != 0) itemListBox.SelectedIndex = 0;
            }
        }