--- a/QTfrontend/ui/page/pagecampaign.cpp	Wed Apr 12 22:04:32 2017 +0200
+++ b/QTfrontend/ui/page/pagecampaign.cpp	Wed Apr 12 23:05:18 2017 +0200
@@ -44,6 +44,7 @@
 
     // set this as default image first time page is created, this will change in hwform.cpp
     btnPreview = formattedButton(":/res/campaign/A_Classic_Fairytale/first_blood.png", true);
+    btnPreview->setWhatsThis(tr("Start fighting"));
     infoLayout->setAlignment(btnPreview, Qt::AlignHCenter | Qt::AlignVCenter);
 
     lbldescription = new QLabel(this);
@@ -87,6 +88,7 @@
     const QIcon& lp = QIcon(":/res/Start.png");
     QSize sz = lp.actualSize(QSize(65535, 65535));
     BtnStartCampaign = new QPushButton();
+    BtnStartCampaign->setWhatsThis(tr("Start fighting"));
     BtnStartCampaign->setStyleSheet("padding: 5px 10px");
     BtnStartCampaign->setText(QPushButton::tr("Start"));
     BtnStartCampaign->setMinimumWidth(sz.width() + 60);

--- a/QTfrontend/ui/page/pagedata.cpp	Wed Apr 12 22:04:32 2017 +0200
+++ b/QTfrontend/ui/page/pagedata.cpp	Wed Apr 12 23:05:18 2017 +0200
@@ -61,6 +61,7 @@
 
     pbOpenDir = addButton(tr("Open packages directory"), bottomLayout, 2, false, Qt::AlignBottom);
     pbOpenDir->setStyleSheet("padding: 5px 10px");
+    pbOpenDir->setWhatsThis(tr("Open the directory in which the downloaded files are stored in your system"));
     pbOpenDir->setMinimumHeight(50);
 
     bottomLayout->setStretch(2, 1);

--- a/QTfrontend/ui/page/pageoptions.cpp	Wed Apr 12 22:04:32 2017 +0200
+++ b/QTfrontend/ui/page/pageoptions.cpp	Wed Apr 12 23:05:18 2017 +0200
@@ -310,10 +310,11 @@
             // Stereo spacing
 
             QLabel * lblStereo = new QLabel(groupGame);
-            lblStereo->setText(QLabel::tr("Stereo rendering"));
+            lblStereo->setText(QLabel::tr("Stereoscopy"));
             groupGame->layout()->addWidget(lblStereo, 4, 0);
 
             CBStereoMode = new QComboBox(groupGame);
+            CBStereoMode->setWhatsThis(QComboBox::tr("Stereoscopy creates an illusion of depth when you wear 3D glasses."));
             CBStereoMode->setMaxVisibleItems(50);
             CBStereoMode->addItem(QComboBox::tr("Disabled"));
             CBStereoMode->addItem(QComboBox::tr("Red/Cyan"));
@@ -419,6 +420,7 @@
 
             CBFrontendEffects = new QCheckBox(groupFrontend);
             CBFrontendEffects->setText(QCheckBox::tr("Visual effects"));
+            CBFrontendEffects->setWhatsThis(QCheckBox::tr("Enable visual effects such as animated menu transitions and falling stars"));
             groupFrontend->layout()->addWidget(CBFrontendEffects, 1, 0);
         }
 
@@ -676,6 +678,7 @@
 
             CBNameWithDate = new QCheckBox(groupMisc);
             CBNameWithDate->setText(QCheckBox::tr("Append date and time to record file name"));
+            CBNameWithDate->setWhatsThis(QCheckBox::tr("If enabled, Hedgewars adds the date and time in the form “YYYY-MM-DD_hh-mm” for automatically created demos."));
             groupMisc->layout()->addWidget(CBNameWithDate, 3, 0, 1, 2);
 
             // Associate file extensions

--- 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();