Don't cancel ThreadWithProgressWindow when it isn't the foremost modal component to allow multiple windows

modules/juce_gui_basics/windows/juce_ThreadWithProgressWindow.cpp

@@ -87,7 +87,7 @@ void ThreadWithProgressWindow::timerCallback()
 {
     bool threadStillRunning = isThreadRunning();
 
-    if (! (threadStillRunning && alertWindow->isCurrentlyModal()))
+    if (! (threadStillRunning && alertWindow->isCurrentlyModal (false)))
     {
         stopTimer();
         stopThread (timeOutMsWhenCancelling);