What is the problem?

If I submit Special:Block form with a validation error, correct the error and resubmit, any page or namespace restriction are not in the created block.

So far, I have only seen this on IE11. I have not seen it on Edge or Firefox.

Comparing IE11 and Firefox, I see on Firefox that after submitting an invalid form any page or namespace selections are stored in a hidden <textarea>. This does not happen on IE11.

Steps to reproduce problem

1. On IE11, go to Special:Block
2. Select the "Partial" radio button and enter any (valid) page and/or namespace
3. Enter some invalid input somewhere else (e.g. enter a non-existent username)
4. Submit the form; should see validation error
5. Correct invalid input from step 3
6. Submit the form

Expected behavior: The block should have the page/namespace restriction entered in step 2
Observed behavior: The block does not have any page/namespace restrictions

Environment

Operating system: Win10
Browser: IE11
Wiki(s): https://en.wikipedia.beta.wmflabs.org/wiki