Improve band combo box pop up list width management

widgets/BandComboBox.cpp

@@ -0,0 +1,27 @@
+#include "BandComboBox.hpp"
+
+#include <QAbstractItemView>
+#include <QScrollBar>
+#include <QDebug>
+#include "models/FrequencyList.hpp"
+
+BandComboBox::BandComboBox (QWidget * parent)
+  : QComboBox {parent}
+{
+}
+
+// Fix up broken QComboBox item view rendering which doesn't allow for
+// a vertical scroll bar in width calculations and ends up eliding the
+// item text.
+void BandComboBox::showPopup ()
+{
+  auto minimum_width = view ()->sizeHintForColumn (FrequencyList_v2::frequency_mhz_column);
+  if (count () > maxVisibleItems ())
+    {
+      // for some as yet unknown reason, in FT8 mode the scrollbar
+      // width is oversize on the first call here
+      minimum_width += view ()->verticalScrollBar ()->width ();
+    }
+  view ()->setMinimumWidth (minimum_width);
+  QComboBox::showPopup ();
+}