Slice - Server Explorer - Lock elements option unavailable

Hi,

I tested this with v4.5.2. Same Arc server, I opened the subset editor in Arc and then I tried it in Slice using the same Arc server.

Lock option is not available in the Subset Editor when using Slice but it is there when using Arc.

Could we please add the Lock option when the Subset Editor is opened in Slice?

Cheers,

Vincent