diff --git a/src/Avalonia.Base/PriorityBindingEntry.cs b/src/Avalonia.Base/PriorityBindingEntry.cs
index 312018d8ee..7f5415c2d8 100644
--- a/src/Avalonia.Base/PriorityBindingEntry.cs
+++ b/src/Avalonia.Base/PriorityBindingEntry.cs
@@ -129,6 +129,8 @@ namespace Avalonia
             }
             else
             {
+                // To avoid allocating closure in the outer scope we need to capture variables
+                // locally. This allows us to skip most of the allocations when on UI thread.
                 var instance = this;
                 var newValue = value;