keybind events aren't mutually exclusive; fix object focus cancelling keybinds; bindable selection box key

Settings.cs

@@ -66,6 +66,7 @@ namespace UIFixes
 
         // Inventory
         public static ConfigEntry<bool> EnableMultiSelect { get; set; }
+        public static ConfigEntry<KeyboardShortcut> SelectionBoxKey { get; set; }
         public static ConfigEntry<MultiSelectStrategy> MultiSelectStrat { get; set; }
         public static ConfigEntry<bool> ShowMultiSelectDebug { get; set; } // Advanced
         public static ConfigEntry<bool> SwapItems { get; set; }
@@ -304,6 +305,15 @@ namespace UIFixes
                     null,
                     new ConfigurationManagerAttributes { })));
 
+            configEntries.Add(SelectionBoxKey = config.Bind(
+                InventorySection,
+                "Selection Box Key",
+                new KeyboardShortcut(KeyCode.Mouse0),
+                new ConfigDescription(
+                    "Mouse button or keyboard key to hold while dragging to create a selection box. Press Reset to use Mouse0 (left mouse button)",
+                    null,
+                    new ConfigurationManagerAttributes { })));
+
             configEntries.Add(MultiSelectStrat = config.Bind(
                 InventorySection,
                 "Multiselect Item Placement",