diff --git a/decode3.F90 b/decode3.F90
index ff4279c5e..a21872873 100644
--- a/decode3.F90
+++ b/decode3.F90
@@ -78,10 +78,10 @@ subroutine decode3(d2,jz,istart,filename)
      call pix2d65(d2d,jz)
   else if(mode.eq.'FSK441') then
      nz=s2(1,1)
-     call pix2d(d2d,jz,mousebutton,mode,s2,64,nz,b)
+     call pix2d(d2d,jz,mousebutton,MouseDF,NFreeze,mode,s2,64,nz,b)
   else if(mode(1:4).eq.'JT6M' .and. mousebutton.eq.0) then
      nz=s2(1,1)
-     call pix2d(d2d,jz,mousebutton,mode,s2,64,nz,b)
+     call pix2d(d2d,jz,mousebutton,MouseDF,NFreeze,mode,s2,64,nz,b)
   endif
 
 ! Compute red and magenta cutves for small plot area, FSK441/JT6M only
diff --git a/pix2d.f90 b/pix2d.f90
index 04656038e..26d6eefbc 100644
--- a/pix2d.f90
+++ b/pix2d.f90
@@ -1,4 +1,4 @@
-subroutine pix2d(d2,jz,mousebutton,mode,s2,nchan,nz,b)
+subroutine pix2d(d2,jz,mousebutton,mousedf,nfreeze,mode,s2,nchan,nz,b)
 
 ! Compute pixels to represent the 2-d spectrum s2(nchan,nz), and the
 ! green line.
@@ -111,6 +111,14 @@ subroutine pix2d(d2,jz,mousebutton,mode,s2,nchan,nz,b)
            b((ich-1)*500+j+248)=254
            b((ich-1)*500+j+495)=254
         enddo
+! Insert green tick at frequency indicated by MouseDF
+        if(NFreeze.gt.0) then
+           f=1076.66+mousedf
+           ich=60-nint(f/43.066)     !Why 58 for FSK441, above?
+           do j=1,7
+              b((ich-1)*500+j+2)=255
+           enddo
+        endif
      endif
 
 ! Mark the best ping with a red tick
diff --git a/wsjt.py b/wsjt.py
index 62fa592d8..564d12efd 100644
--- a/wsjt.py
+++ b/wsjt.py
@@ -1,4 +1,4 @@
-#------------------------------------------------------------------- WSJT
+#------------------------------------------------------------------ WSJT
 
 from Tkinter import *
 from tkFileDialog import *
diff --git a/wsjt1.F b/wsjt1.F
index 732132b24..a214c3b83 100644
--- a/wsjt1.F
+++ b/wsjt1.F
@@ -218,10 +218,12 @@ C  Intentionally degrade SNR by -nclip dB.
 	   if(jz/11025.0.lt.3.9 .or. sigma.lt.0.0) go to 900
 
 	   f0=1076.66
-	   if(NFreeze.eq.1) f0=1076.66+mousedf
+	   if(NFreeze.eq.1) f0=1076.66 + MouseDF
+	   f00=f0
 	   call syncf0(dat,jz,NFreeze,DFTolerance,jstart,f0,smax)
 	   call synct(dat,jz,jstart,f0,smax)
 	   call syncf1(dat,jz,jstart,f0,NFreeze,DFTolerance,smax,red)
+	   if(NFreeze.gt.0 .and. abs(f0-f00).gt.float(DFTolerance)) go to 800
 
 	   f0a=f0
 	   do i=1,512