Disabled option to deselect only layer using CTRL

PixiEditor/Models/DataHolders/Document/Document.Layers.cs

@@ -121,6 +121,10 @@ namespace PixiEditor.Models.DataHolders
             if (index < Layers.Count && index >= 0)
             {
                 Layer layer = Layers[index];
+                if (layer.IsActive && Layers.Count(x => x.IsActive) == 1)
+                {
+                    return;
+                }
                 layer.IsActive = !layer.IsActive;
             }
         }

PixiEditor/Models/Tools/Tools/PenTool.cs

@@ -92,7 +92,7 @@ namespace PixiEditor.Models.Tools.Tools
                 return changes;
             }
 
-            changedPixelsindex += changedPixelsindex >= 2 ? 0 : 1;
+            changedPixelsindex += changedPixelsindex >= 2 ? (byte)0 : (byte)1;
 
             var result = BitmapPixelChanges.FromSingleColoredArray(GetThickShape(latestPixels, toolSize), color);
 

PixiEditor/ViewModels/ViewModelMain.cs

@@ -12,7 +12,6 @@ using PixiEditor.Models.DataHolders;
 using PixiEditor.Models.Dialogs;
 using PixiEditor.Models.Enums;
 using PixiEditor.Models.Events;
-using PixiEditor.Models.IO;
 using PixiEditor.Models.Position;
 using PixiEditor.Models.Tools;
 using PixiEditor.Models.Tools.Tools;

PixiEditor/Views/MainWindow.xaml

@@ -339,7 +339,7 @@
                                                                 <vws:LayerItem.ContextMenu>
                                                                     <ContextMenu>
                                                                         <MenuItem Header="Delete"
-                                                                                  Command="{Binding PlacementTarget.Tag.LayersSubViewModel.DeleteLayerCommand,
+                                                                                  Command="{Binding PlacementTarget.Tag.LayersSubViewModel.DeleteLayersCommand,
                                                                                     RelativeSource={RelativeSource AncestorType=ContextMenu}}"
 
                                                                                   CommandParameter="{Binding RelativeSource={RelativeSource Mode=TemplatedParent},
@@ -361,7 +361,8 @@
                                 Path=(ItemsControl.AlternationIndex)}" />
                                                                         <Separator/>
                                                                         <MenuItem Header="Merge selected"
-                                                                                  Command="{Binding LayersSubViewModel.MergeSelectedCommand, Source={StaticResource ViewModelMain}}"/>
+                                                                                  Command="{Binding PlacementTarget.Tag.LayersSubViewModel.MergeSelectedCommand, 
+                                                                            RelativeSource={RelativeSource AncestorType=ContextMenu}}"/>
                                                                         <MenuItem Header="Merge with above"
                                                                                   Command="{Binding PlacementTarget.Tag.LayersSubViewModel.MergeWithAboveCommand, 
                                                                             RelativeSource={RelativeSource AncestorType=ContextMenu}}"