PowerBuilder PB2022R3 3356, Windows 10 and Window 11

Hi,

I want to execute jscript code with a window. I tried to use the webrowser (WebView2) EvaluateJavaScriptSync() function:

integer		li_rc
string		ls_Result, ls_ErrorMsg
webbrowser	lwb_Object

OpenUserObject( ref lwb_Object )
lwb_Object.Visible = FALSE

// without the MessageBox EvaluateJavaScriptSync(...) returns:
// 	-2 Failed to initialize the control and obtain the WebBrowser object. The WebView2 is invalid. 
// with the MessageBox EvaluateJavaScriptSync(...) returns:
// 	1 und ls_Result is the expected »{"type":"string","value":"lv PowerBuilder"}«
//MessageBox( "", "Continue?" )		// then it works

li_rc = lwb_Object.EvaluateJavaScriptSync( "'lv PowerBuilder';", ref ls_Result, ref ls_ErrorMsg )

CloseUserObject( lwb_Object )
destroy lwb_Object

Why is the call to MessageBox necessary to successfully execute EvaluateJavaScriptSync()? Is there a way to avoid the call to MessageBox or what can I do instead of calling it?
Of course, I can place an invisible webbrowser control on the window. But what is the effect of the call to MessageBox?

Thanks in advence,
Bernhard