Fix deleting materials causing index issues for shapes

Switch_FileFormatsMain/FileFormats/BFRES/BFRESGroupNode.cs

@@ -96,6 +96,7 @@ namespace Bfres.Structs
             if (Type == BRESGroupType.Models)
             {
                 ContextMenuStrip.Items.Add(new STToolStripSeparator());
+                ContextMenuStrip.Items.Add(new STToolStipMenuItem("Show All Models", null, ShowAllModelsAction, Keys.Control | Keys.A));
                 ContextMenuStrip.Items.Add(new STToolStipMenuItem("Hide All Models", null, HideAllModelsAction, Keys.Control | Keys.H));
             }
         }
@@ -107,6 +108,7 @@ namespace Bfres.Structs
         protected void BatchGenerateMipmapsAction(object sender, EventArgs e) { BatchGenerateMipmaps(); }
 
         protected void HideAllModelsAction(object sender, EventArgs e) { HideAllModels(); }
+        protected void ShowAllModelsAction(object sender, EventArgs e) { ShowAllModels(); }
 
         public void BatchGenerateMipmaps()
         {
@@ -117,6 +119,14 @@ namespace Bfres.Structs
             }
         }
 
+        public void ShowAllModels()
+        {
+            for (int i = 0; i < Nodes.Count; i++)
+            {
+                Nodes[i].Checked = true;
+            }
+        }
+
         public void HideAllModels()
         {
             for (int i = 0; i < Nodes.Count; i++)

Switch_FileFormatsMain/FileFormats/BFRES/Bfres Structs/SubFiles/FMDL/FMAT.cs

@@ -150,7 +150,7 @@ namespace Bfres.Structs
             foreach (var shape in model.shapes)
             {
                 //If there are indices higher than this index, shift them
-                if (shape.MaterialIndex > CurrentIndex)
+                if (shape.MaterialIndex >= CurrentIndex)
                 {
                     shape.MaterialIndex -= 1;
                 }