Keep the theme during resize. TODO: preference for wf theme

wfmain.cpp

@@ -1464,7 +1464,7 @@ void wfmain::prepareWf(unsigned int wfLength)
         colorMap->data()->setValueRange(QCPRange(0, wfLength-1));
         colorMap->data()->setKeyRange(QCPRange(0, spectWidth-1));
         colorMap->setDataRange(QCPRange(0, rigCaps.spectAmpMax));
-        colorMap->setGradient(QCPColorGradient::gpJet); // TODO: Add preference
+        colorMap->setGradient(static_cast<QCPColorGradient::GradientPreset>(ui->wfthemeCombo->currentData().toInt()));
 
         if(colorMapData == Q_NULLPTR)
         {