In the 1.6.2 version of Minecraft I've recently ran into this glitch of the fence gates. When I hold any kind of block, tool or anything else whatsoever I can't "toggle" gates regardless their status (being opened or closed).

As in this case a couple of pictures wouldn't help to show the problem itself, I've attached an unlisted YouTube video link below.
https://www.youtube.com/watch?v=LGZgJXd_Hao

I've tried to close the application and the launcher as well, but after the restart it occurs again and again.

I'm not sure if it has anything to do with this minor issue but I use the 32x32 size faithful resource pack without any kind of mods.