I don't know if this is a known bug so I'll post it anyway.
Whenever I tick the shadow feature on, my whole laptop gets stuck at said moment. Then either I get an error which just closes the client (it saying my screen operating system in't working anymore), or it keeps being frozen and I just have to shut down my laptop using the power button.
If I open the client again after the error or restarting my pc, the shadow feature keeps being ticked, so it get's stuck again.
Luckily, there's like 2 seconds (when the screen is loading) at which I can open the option menu and untick the shadows quickly before it's done loading.
I was able to be fast enough to do that so that's solved now.
Just wanted to report this to you guys. Could it be something with my java or graphic card or something like that?
Oh and I tried the same with Ender, same problem there.