diff --git a/rtdata/images/lock_off.png b/rtdata/images/lock_off.png
new file mode 100644
index 000000000..96c1a6da4
Binary files /dev/null and b/rtdata/images/lock_off.png differ
diff --git a/rtdata/images/lock_on.png b/rtdata/images/lock_on.png
new file mode 100644
index 000000000..3e3cf12db
Binary files /dev/null and b/rtdata/images/lock_on.png differ
diff --git a/rtdata/languages/default b/rtdata/languages/default
index c52e8be89..0b674fc2e 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -459,6 +459,7 @@ MAIN_TOOLTIP_HIDEFP;Show/hide the bottom panel (directory and file browser) <b>F
 MAIN_TOOLTIP_HIDEHP;Show/hide the left panel (including the history) <b>l</b>
 MAIN_TOOLTIP_INDCLIPPEDH;Clipped highlight indication (Key <)
 MAIN_TOOLTIP_INDCLIPPEDS;Clipped shadow indication (Key >)
+MAIN_TOOLTIP_BEFOREAFTERLOCK;<b>Lock</b> / <b>Unlock</b> the <b>Before</b> view\n\n<b>Lock</b>: keep the <b>Before</b> view unchanged - \nuseful to evaluate the cumulative effect of multiple tools.\nAdditionally, comparison can be made to any state in the History\n\n<b>Unlock</b>: the <b>Before</b> view will follow the <b>After</b> view 1 step behind, showing image before the effect of the currently used tool
 MAIN_TOOLTIP_PREFERENCES;Set preferences
 MAIN_TOOLTIP_QINFO;Quick info on the image <b>I</b>
 MAIN_TOOLTIP_SAVEAS;Save image to a selected folder
diff --git a/rtgui/editorpanel.cc b/rtgui/editorpanel.cc
index 792ecf1e5..2948ec136 100644
--- a/rtgui/editorpanel.cc
+++ b/rtgui/editorpanel.cc
@@ -82,6 +82,8 @@ EditorPanel::EditorPanel (FilePanel* filePanel)
     beforeAfter->set_relief(Gtk::RELIEF_NONE);
     beforeAfter->set_tooltip_markup (M("MAIN_TOOLTIP_TOGGLE"));
 
+    iBeforeLockON = new Gtk::Image(argv0+"/images/lock_on.png");
+    iBeforeLockOFF = new Gtk::Image(argv0+"/images/lock_off.png");
 
     Gtk::VSeparator* vsept = Gtk::manage (new Gtk::VSeparator ());
     Gtk::VSeparator* vsepz = Gtk::manage (new Gtk::VSeparator ());
@@ -1221,7 +1223,7 @@ void EditorPanel::beforeAfterToggled () {
         return;
 
     removeIfThere (beforeAfterBox,  beforeBox, false);
-    removeIfThere (afterBox,  afterLabel, false);
+    removeIfThere (afterBox,  afterHeaderBox, false);
 
     if (beforeIarea) {
         if (beforeIpc)
@@ -1246,16 +1248,32 @@ void EditorPanel::beforeAfterToggled () {
 
         beforeIarea = new ImageAreaPanel ();
 
+        int HeaderBoxHeight = 15;
+
         beforeLabel = Gtk::manage (new Gtk::Label ());
         beforeLabel->set_markup (Glib::ustring("<b>") + M("GENERAL_BEFORE") + "</b>");
+        tbBeforeLock = Gtk::manage (new Gtk::ToggleButton ());
+        tbBeforeLock->set_tooltip_markup (M("MAIN_TOOLTIP_BEFOREAFTERLOCK"));
+    	tbBeforeLock->signal_toggled().connect( sigc::mem_fun(*this, &EditorPanel::tbBeforeLock_toggled) );
+    	beforeHeaderBox = Gtk::manage (new Gtk::HBox ());
+    	beforeHeaderBox->pack_end (*tbBeforeLock, Gtk::PACK_SHRINK, 2);
+        beforeHeaderBox->pack_end (*beforeLabel, Gtk::PACK_SHRINK, 2);
+        beforeHeaderBox->set_size_request(0, HeaderBoxHeight);
+
+        history->blistenerLock ? tbBeforeLock->set_image (*iBeforeLockON):tbBeforeLock->set_image (*iBeforeLockOFF);
+        tbBeforeLock->set_active(history->blistenerLock);
+
         beforeBox = Gtk::manage (new Gtk::VBox ());
-        beforeBox->pack_start (*beforeLabel, Gtk::PACK_SHRINK, 2);
+        beforeBox->pack_start (*beforeHeaderBox, Gtk::PACK_SHRINK, 2);
         beforeBox->pack_start (*beforeIarea);
 
         afterLabel = Gtk::manage (new Gtk::Label ());
         afterLabel->set_markup (Glib::ustring("<b>") + M("GENERAL_AFTER") + "</b>");
-        afterBox->pack_start (*afterLabel, Gtk::PACK_SHRINK, 2);
-        afterBox->reorder_child (*afterLabel, 0);
+        afterHeaderBox = Gtk::manage (new Gtk::HBox ());
+        afterHeaderBox->set_size_request(0, HeaderBoxHeight);
+        afterHeaderBox->pack_end (*afterLabel, Gtk::PACK_SHRINK, 2);
+        afterBox->pack_start (*afterHeaderBox, Gtk::PACK_SHRINK, 2);
+        afterBox->reorder_child (*afterHeaderBox, 0);
 
         beforeAfterBox->pack_start (*beforeBox);
         beforeAfterBox->reorder_child (*beforeBox, 0);
@@ -1278,6 +1296,11 @@ void EditorPanel::beforeAfterToggled () {
     }
 }
 
+void EditorPanel::tbBeforeLock_toggled () {
+	history->blistenerLock = tbBeforeLock->get_active();
+	tbBeforeLock->get_active()? tbBeforeLock->set_image (*iBeforeLockON) : tbBeforeLock->set_image (*iBeforeLockOFF);
+}
+
 void EditorPanel::histogramChanged (LUTu & histRed, LUTu & histGreen, LUTu & histBlue, LUTu & histLuma, LUTu & histToneCurve, LUTu & histLCurve,
     LUTu & histRedRaw, LUTu & histGreenRaw, LUTu & histBlueRaw) {
 
diff --git a/rtgui/editorpanel.h b/rtgui/editorpanel.h
index 6e8ee6fcf..2bad97523 100644
--- a/rtgui/editorpanel.h
+++ b/rtgui/editorpanel.h
@@ -57,6 +57,7 @@ class EditorPanel : public Gtk::VBox,
         Gtk::ToggleButton* tbShowHideSidePanels;
         Gtk::ToggleButton* tbTopPanel_1;
         Gtk::ToggleButton* tbRightPanel_1;
+        Gtk::ToggleButton* tbBeforeLock;
         bool tbTopPanel_1_Active;
         bool tbRightPanel_1_Active;
         //bool bAllSidePanelsVisible;
@@ -68,6 +69,7 @@ class EditorPanel : public Gtk::VBox,
         Gtk::Image *iTopPanel_1_Show, *iTopPanel_1_Hide;
         Gtk::Image *iRightPanel_1_Show, *iRightPanel_1_Hide;
         Gtk::Image *iShowHideSidePanels;
+        Gtk::Image *iBeforeLockON, *iBeforeLockOFF;
         Gtk::VBox *leftbox;
         Gtk::VBox *vboxright;
 
@@ -85,6 +87,8 @@ class EditorPanel : public Gtk::VBox,
         Gtk::Label* beforeLabel;
         Gtk::Label* afterLabel;
         Gtk::HBox* beforeAfterBox;
+        Gtk::HBox* beforeHeaderBox;
+        Gtk::HBox* afterHeaderBox;
         
         Gtk::Frame* ppframe;
         ProfilePanel* profilep;
@@ -163,6 +167,7 @@ class EditorPanel : public Gtk::VBox,
         void tbRightPanel_1_toggled ();
         void tbTopPanel_1_toggled ();
         void beforeAfterToggled ();
+        void tbBeforeLock_toggled();
         void saveAsPressed ();
         void queueImgPressed ();
         void sendToGimpPressed ();
diff --git a/rtgui/history.cc b/rtgui/history.cc
index 7aca1ba1f..e538ea3c8 100644
--- a/rtgui/history.cc
+++ b/rtgui/history.cc
@@ -27,6 +27,8 @@ extern Glib::ustring argv0;
 
 History::History (bool bookmarkSupport) : blistener(NULL), tpc (NULL), bmnum (1) {
 
+	blistenerLock = false; // sets default that the Before preview will not be locked
+
     // fill history event message array
     for (int i=0; i<NUMOFEVENTS; i++) 
         eventDescrArray[i] = M(Glib::ustring::compose("HISTORY_MSG_%1", i+1));
@@ -145,7 +147,7 @@ void History::historySelectionChanged () {
             ParamsEdited paramsEdited = row[historyColumns.paramsEdited];
             tpc->profileChange (&params, EvHistoryBrowsed, row[historyColumns.text], &paramsEdited);
         }
-        if (blistener) {
+        if (blistener && blistenerLock==false) {
             Gtk::TreeModel::Path path = historyModel->get_path (iter);
             path.prev ();
             iter = historyModel->get_iter (path);
@@ -208,9 +210,9 @@ void History::procParamsChanged (ProcParams* params, ProcEvent ev, Glib::ustring
         newrow[historyColumns.paramsEdited] = paramsEdited ? *paramsEdited : defParamsEdited;
         if (ev!=EvBookmarkSelected)
             selection->select (newrow);
-        if (blistener && row)
+        if (blistener && row && blistenerLock==false)
             blistener->historyBeforeLineChanged (row[historyColumns.params]);
-        else if (blistener && size==0) 
+        else if (blistener && size==0 && blistenerLock==false)
             blistener->historyBeforeLineChanged (newrow[historyColumns.params]);
     }
     // else just update it
diff --git a/rtgui/history.h b/rtgui/history.h
index 134b30b0b..67e4b1e1d 100644
--- a/rtgui/history.h
+++ b/rtgui/history.h
@@ -100,6 +100,8 @@ class History : public Gtk::VBox, public PParamsChangeListener {
 
         void undo ();
         void redo ();
+
+        bool blistenerLock;
 };
 
 #endif