improve UpToFace option of pad/pocket for datum planes

src/Mod/PartDesign/Gui/TaskFeatureParameters.cpp

@@ -27,6 +27,7 @@
 
 #include <Gui/Application.h>
 #include <Gui/Command.h>
+#include <Gui/MainWindow.h>
 #include <Gui/BitmapFactory.h>
 #include <Mod/PartDesign/App/Feature.h>
 #include <Mod/PartDesign/App/Body.h>
@@ -131,7 +132,7 @@ bool TaskDlgFeatureParameters::accept() {
         Gui::Command::commitCommand();
     } catch (const Base::Exception& e) {
         // Generally the only thing that should fail is feature->isValid() others should be fine
-        QMessageBox::warning( 0, tr("Input error"), QString::fromLatin1(e.what()));
+        QMessageBox::warning(Gui::getMainWindow(), tr("Input error"), QString::fromLatin1(e.what()));
         return false;
     }