Fixed behaviour on Windows. Valentina asks about synchronization measurements

twice.
(grafted from e60ffe31f4ba96857a59275dc069bbb67a9bbbdf)

--HG--
branch : develop

ChangeLog.txt

@@ -37,6 +37,7 @@
 - Fix grainline position on layout.
 - [#719] Valentina crashes when unite pieces.
 - Fixed Valentina crash. Used way to avoid Qt's bug QTBUG-61213.
+- Fixed behaviour on Windows. Valentina asks about synchronization measurements twice.
 
 # Version 0.5.0 May 9, 2017
 - [#581] User can now filter input lists by keyword in function wizard.

src/app/valentina/mainwindow.cpp

@@ -184,10 +184,12 @@ MainWindow::MainWindow(QWidget *parent)
     connect(watcher, &QFileSystemWatcher::fileChanged, this, &MainWindow::MeasurementsChanged);
     connect(qApp, &QApplication::focusChanged, this, [this](QWidget *old, QWidget *now)
     {
+        static bool asking = false;
         if (old == nullptr && isAncestorOf(now) == true)
         {// focus IN
-            if (mChanges && not mChangesAsked)
+            if (not asking && mChanges && not mChangesAsked)
             {
+                asking = true;
                 mChangesAsked = true;
                 const auto answer = QMessageBox::question(this, tr("Measurements"),
                                                  tr("Measurements were changed. Do you want to sync measurements now?"),
@@ -196,6 +198,7 @@ MainWindow::MainWindow(QWidget *parent)
                 {
                     SyncMeasurements();
                 }
+                asking = false;
             }
         }