Three connects paired a zero-argument signal with a slot that has a default-valued parameter (e.g. void applyEnable(bool = true)).

Default arguments aren't part of a function's pointer-to-member type, so &Class::slot has a type requiring the argument regardless of its
default value -- incompatible with a signal providing none, and &Class::slot alone won't compile against these signals at all.
When migrating to the modern member pointer connect, replaced  with a lambda that calls the slot with no arguments, letting
the default apply exactly as before.

- SelectAutonumW::applyEnable(bool = true), connected to each  NumPartEditorW's changed() signal in both setContext() and
  on_add_button_clicked(). The corresponding disconnect() in on_remove_button_clicked() is removed rather than reimplemented: a
  lambda-based connection can't be matched and removed by a  separately-written disconnect() call, and the explicit disconnect
  was already redundant -- the very next line deletes the part object, which Qt automatically disconnects on destruction (the same
  guarantee setContext()'s own qDeleteAll() cleanup already relies  on).
- PartText::adjustItemPosition(int = 0), connected to QTextDocument::contentsChanged().
- ExportDialog::slot_changeFilesExtension(bool = false), connected to ExportPropertiesWidget::formatChanged().

sources/editor/graphicspart/parttext.cpp

@@ -55,9 +55,9 @@ PartText::PartText(QETElementEditor *editor, QGraphicsItem *parent) :
 		this, 
 		&PartText::adjustItemPosition);
 	connect(document(),
-		SIGNAL(contentsChanged()),
+		&QTextDocument::contentsChanged,
 		this,
-		SLOT(adjustItemPosition()));
+		[this]() { adjustItemPosition(); });
 }
 
 /// Destructeur