FIX:crash when close preference

JIRA: STUDIO-4340

Change-Id: I95b1c77720bf1264ca70f2fa3652e814d8f20e53

src/slic3r/GUI/Preferences.cpp

@@ -851,7 +851,7 @@ PreferencesDialog::PreferencesDialog(wxWindow *parent, wxWindowID id, const wxSt
                 agent->track_event("preferences_changed", j.dump());
             }
         } catch(...) {}
-        Destroy();
+        event.Skip();
         });
 }