diff --git a/DSView/pv/toolbars/samplingbar.cpp b/DSView/pv/toolbars/samplingbar.cpp
index e01b9a1f..520a471b 100644
--- a/DSView/pv/toolbars/samplingbar.cpp
+++ b/DSView/pv/toolbars/samplingbar.cpp
@@ -722,6 +722,9 @@ double SamplingBar::hori_knob(int dir)
 {
     double hori_res = -1;
 
+    disconnect(&_sample_count, SIGNAL(currentIndexChanged(int)),
+        this, SLOT(on_samplecount_sel(int)));
+
     if (0 == dir) {
         hori_res = commit_hori_res();
     } else if ((dir > 0) && (_sample_count.currentIndex() > 0)) {
@@ -732,9 +735,6 @@ double SamplingBar::hori_knob(int dir)
         hori_res = commit_hori_res();
     }
 
-    disconnect(&_sample_count, SIGNAL(currentIndexChanged(int)),
-        this, SLOT(on_samplecount_sel(int)));
-
     connect(&_sample_count, SIGNAL(currentIndexChanged(int)),
         this, SLOT(on_samplecount_sel(int)));