Building swt against gtk3-3.10.2-1.fc20 I spotted a new warning: "gtk_drag_begin has been deprecated since version 3.10 and should not be used in newly-written code. Use gtk_drag_begin_with_coordinates() instead." Opening devhelp to check documentation for the new function gtk_drag_begin_with_coordinates revealed that documentation for this function is missing in the shipped doc subpackage.
this was a gtk-doc issue that has since been fixed.