diff --git a/src/AppFrame.cpp b/src/AppFrame.cpp
index 92a71b8..9a68285 100644
--- a/src/AppFrame.cpp
+++ b/src/AppFrame.cpp
@@ -34,7 +34,7 @@ EVT_IDLE(AppFrame::OnIdle)
 wxEND_EVENT_TABLE()
 
 AppFrame::AppFrame() :
-        wxFrame(NULL, wxID_ANY, CUBICSDR_TITLE), activeDemodulator(NULL) {
+wxFrame(NULL, wxID_ANY, CUBICSDR_TITLE), activeDemodulator(NULL) {
 
     wxBoxSizer *vbox = new wxBoxSizer(wxVERTICAL);
     wxBoxSizer *demodOpts = new wxBoxSizer(wxVERTICAL);
@@ -405,6 +405,11 @@ void AppFrame::OnIdle(wxIdleEvent& event) {
             mgr->setLastGain(demodGainMeter->getInputValue());
             demodGainMeter->setLevel(demodGainMeter->getInputValue());
         }
+
+        if (wxGetApp().getFrequency() != demodWaterfallCanvas->getCenterFrequency()) {
+            demodWaterfallCanvas->setCenterFrequency(wxGetApp().getFrequency());
+            demodSpectrumCanvas->setCenterFrequency(wxGetApp().getFrequency());
+        }
     }
 
     if (!waterfallCanvas->HasFocus()) {
diff --git a/src/demod/DemodulatorMgr.cpp b/src/demod/DemodulatorMgr.cpp
index 0801915..d26a9e3 100644
--- a/src/demod/DemodulatorMgr.cpp
+++ b/src/demod/DemodulatorMgr.cpp
@@ -115,6 +115,9 @@ void DemodulatorMgr::setActiveDemodulator(DemodulatorInstance *demod, bool tempo
 }
 
 DemodulatorInstance *DemodulatorMgr::getActiveDemodulator() {
+    if (activeDemodulator && !activeDemodulator->isActive()) {
+        activeDemodulator = getLastActiveDemodulator();
+    }
     return activeDemodulator;
 }
 
@@ -144,7 +147,16 @@ void DemodulatorMgr::garbageCollect() {
 
 void DemodulatorMgr::updateLastState() {
     if (std::find(demods.begin(), demods.end(), lastActiveDemodulator) == demods.end()) {
-        lastActiveDemodulator = activeDemodulator;
+        if (activeDemodulator && activeDemodulator->isActive()) {
+            lastActiveDemodulator = activeDemodulator;
+        } else if (activeDemodulator && !activeDemodulator->isActive()){
+            activeDemodulator = NULL;
+            lastActiveDemodulator = NULL;
+        }
+    }
+
+    if (lastActiveDemodulator && !lastActiveDemodulator->isActive()) {
+        lastActiveDemodulator = NULL;
     }
 
     if (lastActiveDemodulator) {
diff --git a/src/sdr/SDRPostThread.cpp b/src/sdr/SDRPostThread.cpp
index 1fa8896..81c9ef4 100644
--- a/src/sdr/SDRPostThread.cpp
+++ b/src/sdr/SDRPostThread.cpp
@@ -196,6 +196,9 @@ void SDRPostThread::threadMain() {
                             }
                         } else if (!demod->isActive()) {
                             demod->setActive(true);
+                            if (wxGetApp().getDemodMgr().getLastActiveDemodulator() == NULL) {
+                                wxGetApp().getDemodMgr().setActiveDemodulator(demod);
+                            }
                         }
 
                         if (!demod->isActive()) {