Crash opening Program.cs in new console app in Mint 20 (Ubuntu 20.04)

[ghost]

command line:
IDE start:

username@computername:~/Git/AvalonStudio/AvalonStudio/AvalonStudio/bin/Debug/netcoreapp3.1$ ./AvalonStudio
radeon: Failed to get PCI ID, error number -13

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create or open solution
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Automatically selecting netcoreapp2.1 as TargetFramework

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select/open cs file:

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Automatically selecting netcoreapp2.1 as TargetFramework
Unhandled exception. System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
at System.Collections.Generic.List1.get_Item(Int32 index) at System.Collections.ObjectModel.Collection1.System.Collections.IList.get_Item(Int32 index)
at Avalonia.Controls.SelectionModel.<>c.<get_SelectedItems>b__39_1(List1 infos, Int32 index) at Avalonia.Controls.SelectionModel.get_SelectedItem() at Avalonia.Controls.Primitives.SelectingItemsControl.OnSelectionModelSelectionChanged(Object sender, SelectionModelSelectionChangedEventArgs e) at Avalonia.Controls.SelectionModel.OnSelectionChanged(SelectionModelSelectionChangedEventArgs e) at Avalonia.Controls.SelectionModel.OnSelectionInvalidatedDueToCollectionChange(Boolean selectionInvalidated, IReadOnlyList1 removedItems)
at Avalonia.Controls.SelectionNode.OnSourceListChanged(Object dataSource, NotifyCollectionChangedEventArgs args)
at Avalonia.Controls.ItemsSourceView.OnItemsSourceChanged(NotifyCollectionChangedEventArgs args)
at Avalonia.Controls.ItemsSourceView.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
at System.Collections.ObjectModel.ObservableCollection1.OnCollectionChanged(NotifyCollectionChangedEventArgs e) at System.Collections.ObjectModel.ObservableCollection1.InsertItem(Int32 index, T item)
at System.Collections.ObjectModel.Collection1.Add(T item) at Dock.Model.FactoryBase.AddDockable(IDock dock, IDockable dockable) at AvalonStudio.Shell.DockExtensions.Dock(IDock dock, IDockableViewModel model, Boolean add) in /home/username/Git/AvalonStudio/AvalonStudio.Shell/src/AvalonStudio.Shell/DockExtensions.cs:line 100 at AvalonStudio.Shell.ShellViewModel.AddDocument(IDocumentTabViewModel document, Boolean temporary, Boolean select) in /home/username/Git/AvalonStudio/AvalonStudio.Shell/src/AvalonStudio.Shell/ShellViewModel.cs:line 278 at AvalonStudio.Shell.IShellExtensions.AddOrSelectDocument[T](IShell me, T document) in /home/username/Git/AvalonStudio/AvalonStudio.Shell/src/AvalonStudio.Shell.Extensibility/Shell/IShellExtensions.cs:line 20 at AvalonStudio.Studio.StudioViewModel.OpenDocumentAsync(ISourceFile file) in /home/username/Git/AvalonStudio/AvalonStudio/AvalonStudio.Studio/StudioViewModel.cs:line 336 at AvalonStudio.Studio.StudioViewModel.OpenDocumentAsync(ISourceFile file, Int32 line, Int32 startColumn, Int32 endColumn, Boolean debugHighlight, Boolean selectLine, Boolean focus) in /home/username/Git/AvalonStudio/AvalonStudio/AvalonStudio.Studio/StudioViewModel.cs:line 346 at AvalonStudio.Controls.Standard.SolutionExplorer.SolutionExplorerViewModel.<>c.<<-ctor>b__7_2>d.MoveNext() in /home/username/Git/AvalonStudio/AvalonStudio/AvalonStudio.Controls.Standard/SolutionExplorer/SolutionExplorerViewModel.cs:line 52 --- End of stack trace from previous location where exception was thrown --- at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__139_0(Object state) at Avalonia.Threading.AvaloniaSynchronizationContext.<>c__DisplayClass8_0.<Post>b__0() at Avalonia.Threading.JobRunner.RunJobs(Nullable1 priority)
at Avalonia.X11.X11PlatformThreading.CheckSignaled()
at Avalonia.X11.X11PlatformThreading.RunLoop(CancellationToken cancellationToken)
at Avalonia.Threading.Dispatcher.MainLoop(CancellationToken cancellationToken)
at Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(String[] args)
at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime[T](T builder, String[] args, ShutdownMode shutdownMode)
at AvalonStudio.Shell.Shell.StartShellApp[TAppBuilder](TAppBuilder builder, String appName, ShellAppMainDelegate main, String[] args, IFactory layoutFactory) in /home/username/Git/AvalonStudio/AvalonStudio.Shell/src/AvalonStudio.Shell/Shell.cs:line 17
at AvalonStudio.Program.Main(String[] args) in /home/username/Git/AvalonStudio/AvalonStudio/AvalonStudio/Program.cs:line 32
Aborted (core dumped)
username@computername:~/Git/AvalonStudio/AvalonStudio/AvalonStudio/bin/Debug/netcoreapp3.1$

sys info:

https://termbin.com/bo9n

[ghost]

Hi! Currently, everyone can use only .NET Core 3.1 & .NET 6 for LTS.