c_gtk_menu_popup_for_device

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
__gshared extern (C)
void function(GtkMenu* menu, GdkDevice* device, GtkWidget* parentMenuShell, GtkWidget* parentMenuItem, GtkMenuPositionFunc func, void* data, GDestroyNotify destroy, guint button, guint32 activateTime) c_gtk_menu_popup_for_device;

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