Can you block reblogs from a specific Tumblr user you follow

Mehper's answer no longer works, as Kirk Woll mentions. As of Feb 2015, you need the following URL to edit:

https://www.tumblr.com/edit/<post_id>?redirect_to=%2Fblog%2F<blog_name>

Replacing < post_id> with your post ID # (example: 406783219) and replacing < blog_name> with the domain of your blog, without the tumblr.com part (example: staff).

https://www.tumblr.com/edit/406783219?redirect_to=%2Fblog%2Fstaff

Obviously, you have to be logged in to your account first, and have the appropriate edit permissions.

Here's the official response from Tumblr support:

Beth, Nov-16 13:33 (EST): Hello,

If you are using a substantial number of tags on your posts, you may find that Tumblr doesn't show all of them in saved tags lists. The list may be shortened in order to ensure the pages where you create and edit posts load quickly.

You can still use as many tags as you wish. But, you will need to fully type out any tags that aren't displayed in the saved tags list. Our apologies for any inconvenience this might cause.

Please let us know if you have any other questions.

Thanks, Beth Tumblr Support support@tumblr.com

So it is expected behaviour, but no mention of what the hard limit is though.

Update from Renee in Tumblr support:

The hard limit for tag autocompletion is "closer to around 100 actually."