Refactor AutoDropShadow logic for clarity and correctness

Flow.Launcher.Core/Resource/Theme.cs

@@ -602,7 +602,7 @@
                 var (backdropType, useDropShadowEffect) = GetActualValue();
 
                 // Remove OS minimizing/maximizing animation
                 // Methods.SetWindowAttribute(new WindowInteropHelper(mainWindow).Handle, DWMWINDOWATTRIBUTE.DWMWA_TRANSITIONS_FORCEDISABLED, 3);
 
                 // The timing of adding the shadow effect should vary depending on whether the theme is transparent.
                 if (BlurEnabled)
@@ -646,7 +646,7 @@
                 backdropType = BackdropTypes.None;
             }
 
             // Dropshadow on and control disabled.(user can't change dropshadow with blur theme)
             if (BlurEnabled)
             {
                 useDropShadowEffect = true;
@@ -670,7 +670,7 @@
             var hasBlur = IsThemeBlurEnabled(dict);
             if (BlurEnabled && hasBlur && Win32Helper.IsBackdropSupported())
             {
                 // If the BackdropType is Mica or MicaAlt, set the windowborderstyle's background to transparent
                 if (backdropType is BackdropTypes.Mica or BackdropTypes.MicaAlt)
                 {
                     windowBorderStyle.Setters.Remove(windowBorderStyle.Setters.OfType<Setter>().FirstOrDefault(x => x.Property == Control.BackgroundProperty));
@@ -706,30 +706,27 @@
 
         private void AutoDropShadow(bool useDropShadowEffect)
         {
-            SetWindowCornerPreference("Default");
-            RemoveDropShadowEffectFromCurrentTheme();
             if (useDropShadowEffect)
             {
                 if (BlurEnabled && Win32Helper.IsBackdropSupported())
                 {
+                    // For themes with blur enabled, the window border is rendered by the system,
+                    // so we set corner preference to round and remove drop shadow effect to avoid rendering issues.
                     SetWindowCornerPreference("Round");
+                    RemoveDropShadowEffectFromCurrentTheme();
                 }
                 else
                 {
+                    // For themes without blur, we set corner preference to default and add drop shadow effect.
                     SetWindowCornerPreference("Default");
                     AddDropShadowEffectToCurrentTheme();
                 }
             }
             else
             {
-                if (BlurEnabled && Win32Helper.IsBackdropSupported())
-                {
-                    SetWindowCornerPreference("Default");
-                }
-                else
-                {
-                    RemoveDropShadowEffectFromCurrentTheme();
-                }
+                // When drop shadow effect is disabled, we set corner preference to default and remove drop shadow effect.
+                SetWindowCornerPreference("Default");
+                RemoveDropShadowEffectFromCurrentTheme();
             }
         }