make sure value label updates even if handle position does not change, fixes #13042

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67379 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/slider.cpp

@@ -439,6 +439,8 @@ void wxSlider::GTKSetValue(int value)
 {
     GTKDisableEvents();
     gtk_range_set_value(GTK_RANGE (m_scale), value);
+    // GTK only updates value label if handle moves at least 1 pixel
+    gtk_widget_queue_draw(m_scale);
     GTKEnableEvents();
 }