diff --git a/plugins/samplesource/bladerf/bladerfgui.cpp b/plugins/samplesource/bladerf/bladerfgui.cpp
index d8dc0f5eb..8b1e245be 100644
--- a/plugins/samplesource/bladerf/bladerfgui.cpp
+++ b/plugins/samplesource/bladerf/bladerfgui.cpp
@@ -30,7 +30,7 @@ BladerfGui::BladerfGui(PluginAPI* pluginAPI, QWidget* parent) :
 	m_sampleSource(NULL)
 {
 	ui->setupUi(this);
-	ui->centerFrequency->setColorMapper(ColorMapper(ColorMapper::Gold));
+	ui->centerFrequency->setColorMapper(ColorMapper(ColorMapper::ReverseGold));
 	ui->centerFrequency->setValueRange(7, BLADERF_FREQUENCY_MIN_XB200/1000, BLADERF_FREQUENCY_MAX/1000);
 	connect(&m_updateTimer, SIGNAL(timeout()), this, SLOT(updateHardware()));
 	displaySettings();
diff --git a/sdrbase/gui/colormapper.cpp b/sdrbase/gui/colormapper.cpp
index 781c82a66..252216549 100644
--- a/sdrbase/gui/colormapper.cpp
+++ b/sdrbase/gui/colormapper.cpp
@@ -36,13 +36,13 @@ ColorMapper::ColorMapper(Theme theme) :
 		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.9, QColor(0x40, 0x23, 0x00)));
 		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(1.0, QColor(0x97, 0x54, 0x00)));
 		*/
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.0, QColor(0x97, 0x54, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.1, QColor(0x5e, 0x34, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.2, QColor(0x5e, 0x34, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.5, QColor(0x00, 0x00, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.8, QColor(0x5e, 0x34, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.9, QColor(0x40, 0x23, 0x00)));
-		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(1.0, QColor(0x97, 0x54, 0x00)));
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.0, QColor(0x97, 0x54, 0x00))); // 59%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.1, QColor(0x5e, 0x34, 0x00))); // 37%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.2, QColor(0x2e, 0x19, 0x00))); // 18%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.5, QColor(0x00, 0x00, 0x00))); //  0%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.8, QColor(0x40, 0x23, 0x00))); // 25%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(0.9, QColor(0x5e, 0x34, 0x00))); // 37%
+		m_dialBackgroundcolorMap.push_back(std::pair<float, QColor>(1.0, QColor(0x97, 0x54, 0x00))); // 59%
 		m_foregroundColor = QColor(0xff, 0x8b, 0x00);
 		m_secondaryForegroundColor = QColor(0xff, 0xc5, 0x80);
 		m_highlightColor = QColor(0xbf, 0x69, 0x00, 0x80);
diff --git a/sdrbase/gui/glspectrumgui.ui b/sdrbase/gui/glspectrumgui.ui
index 220d0a8c7..655742735 100644
--- a/sdrbase/gui/glspectrumgui.ui
+++ b/sdrbase/gui/glspectrumgui.ui
@@ -397,7 +397,7 @@
      <item>
       <widget class="QComboBox" name="fftSize">
        <property name="sizePolicy">
-        <sizepolicy hsizetype="Ignored" vsizetype="Fixed">
+        <sizepolicy hsizetype="Minimum" vsizetype="Fixed">
          <horstretch>0</horstretch>
          <verstretch>0</verstretch>
         </sizepolicy>
@@ -443,13 +443,19 @@
      <item>
       <widget class="QComboBox" name="refLevel">
        <property name="sizePolicy">
-        <sizepolicy hsizetype="Ignored" vsizetype="Fixed">
+        <sizepolicy hsizetype="Minimum" vsizetype="Fixed">
          <horstretch>0</horstretch>
          <verstretch>0</verstretch>
         </sizepolicy>
        </property>
+       <property name="minimumSize">
+        <size>
+         <width>0</width>
+         <height>0</height>
+        </size>
+       </property>
        <property name="toolTip">
-        <string>Reference level</string>
+        <string>Reference level (dB)</string>
        </property>
        <property name="sizeAdjustPolicy">
         <enum>QComboBox::AdjustToContents</enum>
@@ -459,13 +465,19 @@
      <item>
       <widget class="QComboBox" name="levelRange">
        <property name="sizePolicy">
-        <sizepolicy hsizetype="Ignored" vsizetype="Fixed">
+        <sizepolicy hsizetype="Minimum" vsizetype="Fixed">
          <horstretch>0</horstretch>
          <verstretch>0</verstretch>
         </sizepolicy>
        </property>
+       <property name="minimumSize">
+        <size>
+         <width>0</width>
+         <height>0</height>
+        </size>
+       </property>
        <property name="toolTip">
-        <string>Range</string>
+        <string>Range (dB)</string>
        </property>
        <property name="sizeAdjustPolicy">
         <enum>QComboBox::AdjustToContents</enum>