diff --git a/ClassData.h b/ClassData.h
index 358d0fe..ad84196 100644
--- a/ClassData.h
+++ b/ClassData.h
@@ -504,7 +504,12 @@ inline void Data::DecodeBuffer(bool fastDecode, int verbose){
         unsigned long long t0 = Timestamp[ch][(calIndexes[ch][0]) % MaxNData]; // earlier
         unsigned long long t1 = Timestamp[ch][(calIndexes[ch][1]) % MaxNData];; // latest
 
-        if( t0 > t1 ) printf("data is not in time order");
+        if( t0 > t1 ) {
+          printf("digi-%d, ch-%d | data is not in time order\n", boardSN, ch);
+          unsigned long long tt = t1;
+          t1 = t0;
+          t0 = tt;
+        }
 
         double sec = ( t1 - t0 ) * tick2ns / 1e9;
 
diff --git a/FSUDAQ.cpp b/FSUDAQ.cpp
index 4a861f6..f99e917 100644
--- a/FSUDAQ.cpp
+++ b/FSUDAQ.cpp
@@ -50,9 +50,16 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent){
     layoutMain->addWidget(box);
     QGridLayout * layout = new QGridLayout(box);
 
-    bnOpenDigitizers = new QPushButton("Open Digitizers", this);
-    layout->addWidget(bnOpenDigitizers, 0, 0);
-    connect(bnOpenDigitizers, &QPushButton::clicked, this, &MainWindow::OpenDigitizers);
+    cbOpenDigitizers = new RComboBox(this);
+    cbOpenDigitizers->addItem("Open Digitizers ... ", 0);
+    cbOpenDigitizers->addItem("Open Digitizers w/o load Settings", 1);
+    cbOpenDigitizers->addItem("Open Digitizers + load Settings", 2);
+    layout->addWidget(cbOpenDigitizers, 0, 0);
+    connect(cbOpenDigitizers, &RComboBox::currentIndexChanged, this, &MainWindow::OpenDigitizers);
+
+    // bnOpenDigitizers = new QPushButton("Open Digitizers", this);
+    // layout->addWidget(bnOpenDigitizers, 0, 0);
+    // connect(bnOpenDigitizers, &QPushButton::clicked, this, &MainWindow::OpenDigitizers);
     
     bnCloseDigitizers = new QPushButton("Close Digitizers", this);
     layout->addWidget(bnCloseDigitizers, 1, 0);
@@ -594,6 +601,8 @@ void MainWindow::SaveLastRunFile(){
 //***************************************************************
 void MainWindow::OpenDigitizers(){
 
+  if( cbOpenDigitizers->currentIndex() == 0 ) return;
+
   //sereach for digitizers
   LogMsg("Searching digitizers via optical link or USB .....Please wait");
   logMsgHTMLMode = false;
@@ -620,11 +629,17 @@ void MainWindow::OpenDigitizers(){
     LogMsg(QString("Done seraching. No digitizer found."));
     return;
   }else{
-    LogMsg(QString("Done seraching. Found %1 digitizer(s). Opening digitizer(s)....").arg(nDigi));
+
+    if( cbOpenDigitizers->currentIndex() == 1 ) {
+      LogMsg(QString("Done seraching. Found %1 digitizer(s). Opening digitizer(s)....").arg(nDigi));
+    }else{
+      LogMsg(QString("Done seraching. Found %1 digitizer(s). Opening digitizer(s) and load settings....").arg(nDigi));
+    }
   }
   
   digi = new Digitizer * [nDigi];
   readDataThread = new ReadDataThread * [nDigi];
+
   for( unsigned int i = 0; i < nDigi; i++){
     digi[i] = new Digitizer(portList[i].first, portList[i].second);
     //digi[i]->Reset();
@@ -654,14 +669,14 @@ void MainWindow::OpenDigitizers(){
 
     }else{
       LogMsg("Found <b>" + fileName + "</b> for digitizer settings.");
-      
-      // if( digi[i]->LoadSettingBinaryToMemory(fileName.toStdString().c_str()) == 0 ){
-      //   LogMsg("Loaded settings file <b>" + fileName + "</b> for Digi-" + QString::number(digi[i]->GetSerialNumber()));
-      //   digi[i]->ProgramSettingsToBoard();
-        
-      // }else{
-      //   LogMsg("Fail to Loaded settings file " + fileName + " for Digi-" + QString::number(digi[i]->GetSerialNumber()));
-      // }
+      if( cbOpenDigitizers->currentIndex() == 2 ) {
+        if( digi[i]->LoadSettingBinaryToMemory(fileName.toStdString().c_str()) == 0 ){
+          LogMsg("Loaded settings file <b>" + fileName + "</b> for Digi-" + QString::number(digi[i]->GetSerialNumber()));
+          digi[i]->ProgramSettingsToBoard();
+        }else{
+          LogMsg("Fail to Loaded settings file " + fileName + " for Digi-" + QString::number(digi[i]->GetSerialNumber()));
+        }
+      }
     }    
     digi[i]->ReadAllSettingsFromBoard(true);
 
@@ -695,7 +710,9 @@ void MainWindow::OpenDigitizers(){
 
   SetupScalar();
 
-  }
+  cbOpenDigitizers->setCurrentIndex(0);
+
+}
 
 void MainWindow::CloseDigitizers(){
 
@@ -767,7 +784,10 @@ void MainWindow::CloseDigitizers(){
 
 void MainWindow::WaitForDigitizersOpen(bool onOff){
 
-  bnOpenDigitizers->setEnabled(onOff);
+  // bnOpenDigitizers->setEnabled(onOff);
+
+  cbOpenDigitizers->setEnabled(onOff);
+
   bnCloseDigitizers->setEnabled(!onOff);
   bnOpenScope->setEnabled(!onOff);
   bnDigiSettings->setEnabled(!onOff);
diff --git a/FSUDAQ.h b/FSUDAQ.h
index 3138f80..e6d5a73 100644
--- a/FSUDAQ.h
+++ b/FSUDAQ.h
@@ -102,7 +102,9 @@ private:
   unsigned int runID;
   int elogID;
 
-  QPushButton * bnOpenDigitizers;
+  RComboBox * cbOpenDigitizers;
+
+  //QPushButton * bnOpenDigitizers;
   QPushButton * bnCloseDigitizers;
   QPushButton * bnOpenScope;
   QPushButton * bnDigiSettings;
diff --git a/SingleSpectra.cpp b/SingleSpectra.cpp
index 2fb52fc..abbc54a 100644
--- a/SingleSpectra.cpp
+++ b/SingleSpectra.cpp
@@ -13,6 +13,8 @@ SingleSpectra::SingleSpectra(Digitizer ** digi, unsigned int nDigi, QString rawD
   this->nDigi = nDigi;
   this->rawDataPath = rawDataPath;
 
+  isSignalSlotActive = true;
+
   setWindowTitle("1-D Histograms");
   setGeometry(0, 0, 1000, 800);  
   //setWindowFlags( this->windowFlags() & ~Qt::WindowCloseButtonHint );
@@ -31,10 +33,28 @@ SingleSpectra::SingleSpectra(Digitizer ** digi, unsigned int nDigi, QString rawD
     cbDigi = new RComboBox(this);
     for( unsigned int i = 0; i < nDigi; i++) cbDigi->addItem("Digi-" + QString::number( digi[i]->GetSerialNumber() ), i);
     ctrlLayout->addWidget(cbDigi, 0, 0, 1, 2);
-    connect( cbDigi, &RComboBox::currentIndexChanged, this, &SingleSpectra::ChangeHistView);
+    connect( cbDigi, &RComboBox::currentIndexChanged, this, [=](int index){
+      isSignalSlotActive = false;
+      cbCh->clear();
+      for( int i = 0; i < digi[index]->GetNumInputCh(); i++) cbCh->addItem("ch-" + QString::number( i ), i);
+
+      isSignalSlotActive = true;
+
+      if( oldCh >=  digi[index]->GetNumInputCh()) {
+        cbCh->setCurrentIndex(0);
+      }else{
+        if( oldCh >= 0 ){
+          cbCh->setCurrentIndex(oldCh);
+        }else{
+          cbCh->setCurrentIndex(0);
+        }
+      }
+      ChangeHistView();
+      
+    });
 
     cbCh   = new RComboBox(this);
-    for( int i = 0; i < MaxRegChannel; i++) cbCh->addItem("ch-" + QString::number( i ), i);
+    for( int i = 0; i < digi[0]->GetNumInputCh(); i++) cbCh->addItem("ch-" + QString::number( i ), i);
     ctrlLayout->addWidget(cbCh, 0, 2, 1, 2);
     connect( cbCh, &RComboBox::currentIndexChanged, this, &SingleSpectra::ChangeHistView);
 
@@ -42,7 +62,7 @@ SingleSpectra::SingleSpectra(Digitizer ** digi, unsigned int nDigi, QString rawD
     ctrlLayout->addWidget(bnClearHist, 0, 4, 1, 2);
     connect(bnClearHist, &QPushButton::clicked, this, [=](){
       for( unsigned int i = 0; i < nDigi; i++){
-        for( int j = 0; j < MaxRegChannel; j++){
+        for( int j = 0; j < digi[i]->GetNumInputCh(); j++){
           if( hist[i][j] ) hist[i][j]->Clear();
           lastFilledIndex[i][j] = -1;
           loopFilledIndex[i][j] = 0;
@@ -116,6 +136,8 @@ void SingleSpectra::ClearInternalDataCount(){
 
 void SingleSpectra::ChangeHistView(){
 
+  if( !isSignalSlotActive ) return;
+
   if( oldCh >= 0 ) {
     histLayout->removeWidget(hist[oldBd][oldCh]);
     hist[oldBd][oldCh]->setParent(nullptr);
diff --git a/SingleSpectra.h b/SingleSpectra.h
index 95fec55..cc0e4b6 100644
--- a/SingleSpectra.h
+++ b/SingleSpectra.h
@@ -61,5 +61,7 @@ private:
 
   QString rawDataPath;
 
+  bool isSignalSlotActive;
+
 };
 #endif
\ No newline at end of file