FIX: remove duplicate CMakeLists sources and leak timer_sync_printer

F-010: Scrollbar.cpp and ScrolledWindow.cpp were listed twice in
SLIC3R_GUI_SOURCES (lines 39/41 and 73/75), violating the ODR and
inflating incremental build time for those translation units.

F-006: Sidebar::priv::~priv() never deleted timer_sync_printer, which
is heap-allocated at member initialisation (= new wxTimer()). Add
Stop() + delete in the destructor to plug the leak on application exit.

Ref: #10289

Author: tinezivic

src/slic3r/CMakeLists.txt

@@ -70,10 +70,6 @@ set(SLIC3R_GUI_SOURCES
     GUI/Widgets/FilamentLoad.hpp
     GUI/Widgets/FanControl.cpp
     GUI/Widgets/FanControl.hpp
-    GUI/Widgets/Scrollbar.cpp
-    GUI/Widgets/Scrollbar.hpp
-    GUI/Widgets/ScrolledWindow.cpp
-    GUI/Widgets/ScrolledWindow.hpp
     GUI/Widgets/StepCtrl.cpp
     GUI/Widgets/StepCtrl.hpp
     GUI/Widgets/ProgressBar.cpp

src/slic3r/GUI/Plater.cpp

@@ -996,6 +996,12 @@ void Sidebar::priv::show_fila_switch_msg(bool ready)
 
 Sidebar::priv::~priv()
 {
+    // Stop and delete the printer-sync timer to prevent resource leak
+    if (timer_sync_printer) {
+        timer_sync_printer->Stop();
+        delete timer_sync_printer;
+        timer_sync_printer = nullptr;
+    }
     // BBS
     //delete object_manipulation;
     delete object_settings;