tdf#104573 - Assertion failed: SolarMutex not locked when trying

to bring up File Open... dialog

we need to hold the SolarMutex when doing VclPtr ref-counting

Change-Id: I843f2a243acaf73db1f6557df23475fe5bb12131
Reviewed-on: https://gerrit.libreoffice.org/31892
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

vcl/source/window/event.cxx

@@ -652,6 +652,7 @@ void Window::ImplCallFocusChangeActivate( vcl::Window* pNewOverlapWindow,
 NotifyEvent::NotifyEvent( MouseNotifyEvent nEventType, vcl::Window* pWindow,
                           const void* pEvent )
 {
+    SolarMutexGuard aVclGuard;
     mpWindow    = pWindow;
     mpData      = const_cast<void*>(pEvent);
     mnEventType  = nEventType;