1 files changed, 32 insertions, 1 deletions

diff --git a/src/extension/prefdialog.cpp b/src/extension/prefdialog.cpp
index 0247e18e9..0861f1dc3 100644
--- a/src/extension/prefdialog.cpp
+++ b/src/extension/prefdialog.cpp
@@ -18,6 +18,8 @@
 // Used to get SP_ACTIVE_DESKTOP
 #include "inkscape.h"
 #include "desktop.h"
+#include "document.h"
+#include "document-undo.h"
 
 #include "effect.h"
 #include "implementation/implementation.h"
@@ -61,6 +63,13 @@ PrefDialog::PrefDialog (Glib::ustring name, gchar const * help, Gtk::Widget * co
         controls = _effect->get_imp()->prefs_effect(_effect, SP_ACTIVE_DESKTOP, &_signal_param_change, NULL);
         _signal_param_change.connect(sigc::mem_fun(this, &PrefDialog::param_change));
     }
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if (desktop) {
+        Inkscape::Selection * selection = desktop->getSelection();
+        if (selection) {
+            selection->emptyBackup();
+        }
+    }
     hbox->pack_start(*controls, true, true, 0);
     hbox->show();
 
@@ -170,12 +179,29 @@ PrefDialog::run (void) {
 
 void
 PrefDialog::preview_toggle (void) {
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    SPDocument *document = SP_ACTIVE_DOCUMENT;
+    Inkscape::Selection * selection = NULL;
+    bool modified = document->isModifiedSinceSave();
+    if(desktop) {
+        selection = desktop->getSelection();
+        if (!selection->isEmpty()) {
+            selection->setBackup();
+        }
+    }
     if(_param_preview->get_bool(NULL, NULL)) {
-        set_modal(true);
         if (_exEnv == NULL) {
+            set_modal(true);
+            if (desktop && selection) {
+                desktop->on_live_extension = true;
+                
+            }
             _exEnv = new ExecutionEnv(_effect, SP_ACTIVE_DESKTOP, NULL, false, false);
             _effect->set_execution_env(_exEnv);
             _exEnv->run();
+            if (desktop && selection) {
+                selection->clear();
+            }
         }
     } else {
         set_modal(false);
@@ -185,8 +211,13 @@ PrefDialog::preview_toggle (void) {
             delete _exEnv;
             _exEnv = NULL;
             _effect->set_execution_env(_exEnv);
+            if (desktop && selection) {
+                selection->restoreBackup();
+                desktop->on_live_extension = false;
+            }
         }
     }
+    document->setModifiedSinceSave(modified);
 }
 
 void