Blazor WebAssembly - HTML select tag with @onchange event does not hit breakpoint when clicking to select values from dropdown using the cursor, but works with up/down key from keyboard

[Marques01]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In .NET8 and .NET9, in a new Blazor WebAssembly app, when using a <select> tag, with the @onchange event, if I put a breakpoint in the method being triggered (i.e. @onchange="Test"), the breakpoint will not be hit if I click on different values in the dropdown using the mouse.
However, the breakpoint is being hit fine when using the up/down keys from the keyboard.

<input> works @onchange event, but <select> no

In addition, when using the mouse, I can see that the method is run and states are changed - the issue I experienced is the breakpoint that is not being hit.

Additional info: doing the same in .NET6 works fine, and breakpoint is being hit just fine in all cases.

@page "/"
<label class="form-label">Countries</label>
<select class="form-select" @onchange="OnCountryChanged">
    <option value="1">USA></option>
    <option value="2">Canada</option>
    <option value="3">Mexico</option>
</select>
@code {

    private void OnCountryChanged(ChangeEventArgs e)
    {
    }

}

reference: dotnet/aspnetcore#58615

Expected Behavior

Breakpoint is being hit when using the mouse/cursor to select different values from a select statement with the @onchange event

Steps To Reproduce

Create a new Blazor Web Assembly (WASM) project in VS2022.
Add a select tag to any page (I did it to the Counter component)
add the @onchange event to the select tag, and assign it with a method
Put a breakpoint in the method assigned to the @onchange event
Run the app, click on different values in the dropdown, and see that the breakpoint is not being hit.
Then, try selecting using different values using the up/down keys from the keyboard, and the breakpoint should be hit

Exceptions (if any)

No response

.NET Version

No response

Anything else?

No response

[phil-allen-msft]

The original poster says that it fires as expected in Net6 but not Net8 or Net9. Need to verify if the binding referenced in the @onchange isn't being called from mouse clicks in the same way as keyboard changes at runtime.