UI sometimes becomes uninteractive with the mouse after selecting a file from a file input (.NET MAUI Blazor)

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Issue moved from dotnet/maui#15072

• Please respond to @DennisvHest.

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From @DennisvHest on Saturday, May 13, 2023 8:07:59 PM

Description

Sometimes after selecting a file using a file input, the application can no longer be interacted with using the mouse. The application is not frozen however, because you can still interact with the keyboard.

It happens very inconsistantly. Sometimes I can reproduce it immediately, other times I have to select like 20 files before the bug occurs.

Once the bug occurs, the mouse interactivity can be restored by moving the mouse cursor out of the window. After that you can interact with the mouse again.

UPDATE (14-01-2024): After updating to .NET 8, instead of the original bug occuring, the application crashes.

https://github.com/dotnet/maui/assets/18610083/28ba1536-86ce-4245-acaf-636b8fd051b1

Steps to Reproduce

1. Create a File > New .NET MAUI Blazor App
2. Add the following code to the index.razor page:

@page "/"

<input type="file" />
<b>Counter: @counter</b>
<button @onclick="IncrementCount">count</button>

@code {
    int counter = 0;

    void IncrementCount()
    {
        counter++;
    }
}

3. Select a file using the file input
4. Try to click the count button
5. If you can still click the count button, repeat steps 3 and 4 (it might take like 20 times for the bug to occur)
6. If the bug occurs (count button cannot be clicked), move the mouse outside of the window
7. The count button can now be clicked again

Expected outcome: page stays interactive
Actual outcome: page is no longer interactive using the mouse
.NET 8 Update: application now crashes when this occurs

Link to public reproduction project repository

https://github.com/DennisvHest/FileInputBugTest

Version with bug

8.0 (current)

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows 10 22H2, Windows App SDK 1.3.230502000

Did you find any workaround?

Haven't found a workaround for this.

Relevant log output

No response

AB#50879737

Start with the linked FileInputBugTest reproduction project and its index.razor example, then run the file-selection steps on Windows 10 with .NET 8. Compare the intermittent mouse lockup with the reported crash and verify whether moving the pointer outside the window changes behavior. Done means the reproduction remains interactive with the mouse after repeated file selections.