Fixes broken selection of WB, crop and straighten from toolbar (#5286)

Improvements:
- When switching between notebook pages different from Locallab one,
edit tools aren't anymore unsubscribed for better robustness

rtgui/toolpanelcoord.h

@@ -207,6 +207,7 @@ private:
     EditDataProvider *editDataProvider;
     sigc::connection notebookconn;
     bool photoLoadedOnce; // Used to indicated that a photo has been loaded yet
+    Gtk::Widget* prevPage;
 
 public:
     CoarsePanel* coarse;