diff -r 8db93a3a29dc -r 88b31fdc760b QTfrontend/ui/page/pagetraining.cpp
--- a/QTfrontend/ui/page/pagetraining.cpp	Wed Apr 12 22:04:32 2017 +0200
+++ b/QTfrontend/ui/page/pagetraining.cpp	Wed Apr 12 23:05:18 2017 +0200
@@ -279,6 +279,8 @@
             else
                 btnPreview->setIcon(QIcon(":/res/Trainings.png"));
 
+            btnPreview->setWhatsThis(tr("Start fighting"));
+
             QString realName = list->currentItem()->data(
                                     Qt::UserRole).toString();