dia.Paper: improve preventing image dragging in Firefox (#790)
dia.Paper: improve preventing image dragging in Firefox (#790)


kumilingus/joint,kumilingus/joint,clientIO/joint,DavidDurman/joint,gagaboy/joint,vtalas/joint,clientIO/joint,vtalas/joint,kumilingus/joint,clientIO/joint,gagaboy/joint,clientIO/joint,vtalas/joint,kumilingus/joint,gagaboy/joint,DavidDurman/joint,DavidDurman/joint