set background color for tooltips

GUI/View/Base/Stylesheet.cpp

@@ -30,5 +30,6 @@ void GUI::Style::setInitialStyle()
     styleSheetPalette.setColor(QPalette::Base, Qt::white);
     styleSheetPalette.setColor(QPalette::AlternateBase, QColor(255, 255, 255).darker(105));
     styleSheetPalette.setColor(QPalette::Dark, QColor(255, 255, 255).darker(110));
+    styleSheetPalette.setColor(QPalette::ToolTipBase, QColor(174, 248, 255));
     QApplication::setPalette(styleSheetPalette);
 }

GUI/styles/Base.stylesheet

@@ -30,6 +30,12 @@ QWidget#SampleSummary
     border: 0px;
 }
 
+/* ------------------------------------------------------------------------------- */
+QToolTip
+{
+    background-color: palette(tooltipbase);
+}
+
 /* ------------------------------------------------------------------------------- */
 QLabel
 {