diff --git a/src/avtk/avtk_button.h b/src/avtk/avtk_button.h
index 376f4b2..a77030a 100644
--- a/src/avtk/avtk_button.h
+++ b/src/avtk/avtk_button.h
@@ -49,8 +49,17 @@ class Button : public Fl_Button
       
       highlight = false;
       mouseOver = false;
+      
+      greyedOut = false;
     }
     
+    void setGreyOut( bool g )
+    {
+      greyedOut = g;
+    }
+    
+    bool greyedOut;
+    
     bool mouseOver;
     bool highlight;
     int x, y, w, h;
@@ -95,13 +104,19 @@ class Button : public Fl_Button
         cairo_save( cr );
         
         cairo_rectangle( cr, x+1, y+1, w-2, h-2 );
-        cairo_set_source_rgb( cr, _bgr, _bgg, _bgb );
+        if ( !greyedOut )
+          cairo_set_source_rgb( cr, _bgr, _bgg, _bgb );
+        else
+        {
+          float grey = (_bgr + _bgg + _bgb) / 3;
+          cairo_set_source_rgb( cr, grey, grey, grey );
+        }
         cairo_fill_preserve(cr);
         
         cairo_set_line_width(cr, 1.3);
         cairo_rectangle( cr, x+1, y+1, w-2, h-2 );
         
-        if ( highlight )
+        if ( highlight && !greyedOut )
         {
           cairo_set_source_rgba(cr, _r, _g, _b, 0.4);
           cairo_fill_preserve(cr);
@@ -110,8 +125,16 @@ class Button : public Fl_Button
         float alpha = 0.6;
         if (mouseOver)
           alpha = 1;
-        cairo_set_source_rgba(cr,  _r, _g, _b, alpha);
-        if ( highlight )
+        
+        if ( !greyedOut )
+          cairo_set_source_rgba(cr,  _r, _g, _b, alpha);
+        else
+        {
+          float grey = (_r + _g + _b) / 3;
+          cairo_set_source_rgb( cr, grey, grey, grey );
+        }
+        
+        if ( highlight && !greyedOut )
           cairo_set_line_width(cr, 2.2);
         cairo_stroke(cr);
         
diff --git a/src/gaudioeditor.cxx b/src/gaudioeditor.cxx
index 325f2b1..6a33a88 100644
--- a/src/gaudioeditor.cxx
+++ b/src/gaudioeditor.cxx
@@ -22,6 +22,8 @@
 #include <sstream>
 
 #include "config.hxx"
+#include "gui.hxx"
+extern Gui* gui;
 
 #include "audiobuffer.hxx"
 
@@ -84,11 +86,86 @@ void AudioEditor::show( AudioBuffer* buf, bool modal )
   else
   {
     std::vector<float>& tmp = ab->getData();
-    waveform->setData( &tmp[0], tmp.size() );
+    int size = tmp.size();
+    waveform->setData( &tmp[0], size );
+    
+    const int beats[]={1,2,4,8,16,32,64};
+    
+    int iBeatOne = -1;
+    int iBeatTwo = -1;
+    
+    // figure out BPM values from size
+    for( int i = 0; i < 7; i++ )
+    {
+      int beat = beats[i];
+      
+      int fpb = size / beat;
+      
+      int bpm = (gui->samplerate / fpb) * 60;
+      
+      
+      if ( bpm < 60 || bpm > 220 )
+      {
+        // disable option: not valid
+        beatButtons[i]->setGreyOut( true );
+        beatButtons[i]->setColor( 0.4, 0.4, 0.4 );
+      }
+      else
+      {
+        printf("%i, fpb = %i, bpm= = %i\n", beat, fpb, bpm );
+        // enable option ( may be disabled previously! )
+        beatButtons[i]->setGreyOut( false );
+        
+        // remember this beat was a valid one, to check for best match
+        if ( iBeatOne == -1 )
+          iBeatOne = i;
+        else
+          iBeatTwo = i;
+      }
+    }
+    
+    // both valid: compare, and adjust color
+    if ( iBeatOne != -1 && iBeatTwo != -1 )
+    {
+      int masterFpb = (gui->samplerate * 60) / gui->getMasterTrack()->getBpm();
+      int oneFpb = size / beats[iBeatOne];
+      int twoFpb = size / beats[iBeatTwo];
+      
+      int oneDelta = masterFpb - oneFpb;
+      int twoDelta = masterFpb - twoFpb;
+      
+      if ( oneDelta < 0 ) oneDelta = -oneDelta;
+      if ( twoDelta < 0 ) twoDelta = -twoDelta;
+      
+      if ( oneDelta == twoDelta )
+      {
+        beatButtons[iBeatOne]->setColor( 0.0, 1.0, 0.0 );
+        beatButtons[iBeatTwo]->setColor( 0.0, 1.0, 0.0 );
+      }
+      else if ( oneDelta <= twoDelta )
+      {
+        // one is the better match
+        beatButtons[iBeatOne]->setColor( 0.0, 1.0, 0.0 );
+        beatButtons[iBeatTwo]->setColor( 1.0, 0.0, 0.0 );
+      }
+      else
+      {
+        beatButtons[iBeatTwo]->setColor( 0.0, 1.0, 0.0 );
+        beatButtons[iBeatOne]->setColor( 1.0, 0.0, 0.0 );
+      }
+    }
+    else if( iBeatOne != -1 && iBeatTwo == -1) // only one valid
+    {
+      beatButtons[iBeatOne]->setColor( 0.0, 1.0, 0.0 );
+    }
+    else
+    {
+      // no valid BPM range..?
+    }
+    
   }
   
   window->set_modal();
-  
   window->show();
 }