Exception error "Nullable object must have a value." (New regression bug from 5.26.3 that just released)

[gileli121]

Recently, a report was received about a different error that has never been reported before:

**Version: v5.26.3
Type: MS Store
Installed: Yes
IsAdminHelper: No
IsAdmin: No

5ZH8X: [Error] Got fatal exception and handled by App_OnDispatcherUnhandledException: System.InvalidOperationException: Nullable object must have a value.
at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at m1e.o1S.R1G()
at dEG.kEI.i5M()
at dEG.kEI.r5F.E56(Object , EventArgs )
at System.Windows.Threading.DispatcherTimer.FireTick(Object unused)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
5ZH8X: [Info] SetLanguage called
5ZH8X: [Info] SetLanguage is falling back to default language
5ZH8X: [Info] SetLanguage is configuring language en

**Exception:
System.InvalidOperationException: Nullable object must have a value.
at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at m1e.o1S.R1G()
at dEG.kEI.i5M()
at dEG.kEI.r5F.E56(Object , EventArgs )
at System.Windows.Threading.DispatcherTimer.FireTick(Object unused)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

It seems to be something very new that started occurring with version 5.26.3, which was released just a few days ago.

After a thorough examination of the code, it appears that the issue is linked to the rewritten code responsible for the toolbar and arrow (#402). Upon closer inspection, it seems there is a race condition causing this type of error.

[gileli121]

While working on the fix, it’s possible that this correction also resolved similar errors that, in hindsight, were likely caused by the same issue in the code I just fixed. After this fix, the software may operate more stably, potentially without several other similar errors reported in the past.

[gileli121]

Fixed in 5.26.5
https://github.com/WindowTop/WindowTop-App/releases/tag/5.26