Revert of the 84c6199015

Note: When ProgressDialog has no-nullptr parent, then PrusaSlicer doesn't lose the focus at the end of model fixing,
but start to flickering during fixing of the big models.

src/slic3r/GUI/Plater.cpp

@@ -3503,6 +3503,8 @@ void Plater::priv::fix_through_netfabb(const int obj_idx, const int vol_idx/* =
     ModelObject* mo = model.objects[obj_idx];
     fix_model_by_win10_sdk_gui(*mo, vol_idx);
     q->changed_mesh(obj_idx);
+    // workaround to fix the issue, when PrusaSlicer lose a focus after model fixing
+    q->SetFocus();
 }
 
 void Plater::priv::set_current_panel(wxPanel* panel)

src/slic3r/Utils/FixModelByWin10.cpp

@@ -36,8 +36,6 @@
 #include "../GUI/GUI.hpp"
 #include "../GUI/I18N.hpp"
 #include "../GUI/MsgDialog.hpp"
-#include "../GUI/GUI_App.hpp"
-#include "../GUI/MainFrame.hpp"
 
 #include <wx/msgdlg.h>
 #include <wx/progdlg.h>
@@ -343,7 +341,7 @@ void fix_model_by_win10_sdk_gui(ModelObject &model_object, int volume_idx)
 	wxProgressDialog progress_dialog(
 		_L("Model fixing"),
 		_L("Exporting model") + "...",
-		100, GUI::wxGetApp().mainframe, wxPD_AUTO_HIDE | wxPD_APP_MODAL | wxPD_CAN_ABORT);
+		100, nullptr, wxPD_AUTO_HIDE | wxPD_APP_MODAL | wxPD_CAN_ABORT);  // ! parent of the wxProgressDialog should be nullptr to avoid flickering during the model fixing
 	// Executing the calculation in a background thread, so that the COM context could be created with its own threading model.
 	// (It seems like wxWidgets initialize the COM contex as single threaded and we need a multi-threaded context).
 	bool   success = false;