Some fixes

Author: rds1983

src/Myra/Graphics2D/UI/Containers/ScrollViewer.cs

@@ -578,7 +578,7 @@ protected override void InternalArrange()
 					_thumbMaximumY = 1;
 				}
 
-				if (_horizontalScrollingOn)
+				if (_horizontalScrollingOn && ShowHorizontalScrollBar)
 				{
 					bounds.Width = measureSize.X;
 				}
@@ -587,7 +587,7 @@ protected override void InternalArrange()
 					bounds.Width = availableSize.X;
 				}
 
-				if (_verticalScrollingOn)
+				if (_verticalScrollingOn && ShowVerticalScrollBar)
 				{
 					bounds.Height = measureSize.Y;
 				}

src/Myra/Graphics2D/UI/Desktop.cs

@@ -314,6 +314,7 @@ public Desktop()
 			KeyDownHandler = OnKeyDown;
 
 #if FNA
+			TextInputEXT.StartTextInput();
 			TextInputEXT.TextInput += OnChar;
 #endif
 

src/Myra/Graphics2D/UI/File/FileDialog.cs

@@ -177,6 +177,13 @@ public FileDialog(FileDialogMode mode) : base(null)
 			SetStyle(Stylesheet.DefaultStyleName);
 		}
 
+		protected override void OnPlacedChanged()
+		{
+			base.OnPlacedChanged();
+
+			UpdateFolder();
+		}
+
 		/// <summary>
 		/// Create the navigation menu of places we can visit.
 		/// </summary>
@@ -401,6 +408,11 @@ private void UpdateFolder()
 			_paths.Clear();
 
 			_scrollPane.ScrollPosition = Mathematics.PointZero;
+
+			if (Desktop == null)
+			{
+				return;
+			}
 
 			var path = _textFieldPath.Text;