Some fixes

Author: rds1983

Directory.Build.props

@@ -7,7 +7,7 @@
     <RootNamespace>Myra</RootNamespace>
     <Description>UI Library for MonoGame, FNA and Stride</Description>
     <VersionPrefix>1.5.8</VersionPrefix>
-    <XNAssetsVersion>0.7.3</XNAssetsVersion>
+    <XNAssetsVersion>0.7.5</XNAssetsVersion>
     <FontStashSharpVersion>1.3.9</FontStashSharpVersion>
     <LangVersion>8.0</LangVersion>
     <InfoLundinMathVersion>1.2.6</InfoLundinMathVersion>

src/Myra/Graphics2D/UI/Properties/PropertyGrid.cs

@@ -1220,6 +1220,10 @@ private void FillSubGrid(ref int y, IReadOnlyList<Record> records)
 				{
 					valueWidget = CreateFileEditor(record, hasSetter, "*.png|*.jpg|*.bmp|*.gif", name => Settings.AssetManager.LoadTexture2D(MyraEnvironment.GraphicsDevice, name));
 				}
+				else if (propertyType == typeof(TextureCube))
+				{
+					valueWidget = CreateFileEditor(record, hasSetter, "*.dds", name => Settings.AssetManager.LoadTexture2D(MyraEnvironment.GraphicsDevice, name));
+				}
 #endif
 				else
 				{

src/Myra/Graphics2D/UI/Selectors/ListView.cs

@@ -288,7 +288,13 @@ public int? SelectedIndex
 					return null;
 				}
 
-				return Widgets.IndexOf(_selectedItem);
+				var result = Widgets.IndexOf(_selectedItem);
+				if (result == -1)
+				{
+					return null;
+				}
+
+				return result;
 			}
 
 			set