Windows 10: Crash in MDI-App after maximizing an MDI-window and clicking on window icon

[MartinK222]

• Run MDI Example
• Create MDI window
• Maximize window by doubleclick on captionbar (little icon left to filemenu appears)
• Click on little icon left to filemenu (marked by red box)
• Crash

Running Windows 10.0.19045, wxWidgets 3.0 (private build from source, gcc 15.0)

[MaartenBent]

I think this is caused by c1e2acd from #24874.

When searching the sub-menus, it finds a menu item with wID 0 that has valid MIIM_DATA and tries to cast it to a wxMenuItem. But it is some other data (not set by wxWidgets) causing the wxMenuItem to be a broken object and a later call to menuItem->GetHelp() causes an memory access violation.

wxWidgets/src/msw/window.cpp

Lines 2539 to 2543 in 66bd59a

	wxMenuItem* menuItem = (wxMenuItem*)mii.dwItemData;
	if ( mii.wID == (unsigned int)item && menuItem )
	{
	return menuItem;
	}

Maybe the fix is to only search for menu items when the wxMenu is not nullptr in the code below. Or can there be a wxMenuItem event without a wxMenu?

wxWidgets/src/msw/window.cpp

Lines 2477 to 2478 in 66bd59a

	wxMenu* menu = MSWFindMenuFromHMENU(hMenu);
	wxMenuItem* menuItem = MSWFindMenuItemFromHMENU(hMenu, item);

cc #25505 which also is about this code.

[vadz]

Is the version ("3.0") in the report really correct or is it with 3.3.0?

[MartinK222]

Is the version ("3.0") in the report really correct or is it with 3.3.0?

Sorry. It's 3.3.0.

[MartinK222]

Crash is in function wxFrameBase::OnMenuHighlight calling DoGiveHelp(menuItem->GetHelp(), true);

Stacktrace:
wxmsw330ud_gcc_custom.dll!std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::size
wxmsw330ud_gcc_custom.dll!std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::length
wxmsw330ud_gcc_custom.dll!std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::_M_assign
wxmsw330ud_gcc_custom.dll!std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::assign
wxmsw330ud_gcc_custom.dll!std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::operator=
wxmsw330ud_gcc_custom.dll!wxString::operator=
wxmsw330ud_gcc_custom.dll!wxFrameBase::DoGiveHelp

[vadz]

Please see #25540 for the fix.

Thanks for reporting this!

[MartinK222]

Please see #25540 for the fix.

Thanks for reporting this!

Thanks for fixing this!