fix:issue #178 #177

Ink Canvas/MainWindow_cs/MW_Eraser.cs

@@ -750,6 +750,10 @@ namespace Ink_Canvas
                     {
                         overlay.CaptureMouse();
                         StartAdvancedEraserOperation(sender);
+                        
+                        // 处理单点擦除
+                        var position = e.GetPosition((UIElement)FindName("inkCanvas"));
+                        UpdateAdvancedEraserPosition(sender, position);
                     }
                 };
 
@@ -787,6 +791,10 @@ namespace Ink_Canvas
                             overlay.CaptureStylus();
                         }
                         StartAdvancedEraserOperation(sender);
+                        
+                        // 处理单点擦除
+                        var position = e.GetPosition((UIElement)FindName("inkCanvas"));
+                        UpdateAdvancedEraserPosition(sender, position);
                     }
                 };
 

Ink Canvas/MainWindow_cs/MW_PPT.cs

@@ -232,10 +232,10 @@ namespace Ink_Canvas
                 pptApplication = new Microsoft.Office.Interop.PowerPoint.Application();
                 
                 // 设置为不可见，作为后台进程
-                pptApplication.Visible = Microsoft.Office.Core.MsoTriState.msoFalse;
+                pptApplication.Visible = MsoTriState.msoFalse;
                 
                 // 设置应用程序属性
-                pptApplication.WindowState = Microsoft.Office.Interop.PowerPoint.PpWindowState.ppWindowMinimized;
+                pptApplication.WindowState = PpWindowState.ppWindowMinimized;
 
                 // 直接设置PPTManager的PPTApplication属性，绕过COM注册问题
                 Task.Delay(1000).ContinueWith(_ =>