#4458 Preview doesn't work when adding a new column

[Isaac Bennetch]

I'm having a bit of difficulty with this feature; in my case I go to the structure page of an existing table and click the button to add a new column. On the resulting page (where I can set the column type for the new column), there is a Preview SQL button. Clicking that button results in an empty dialog box, and the query actually runs anyway.

[Marc Delisle]

Fix: https://github.com/phpmyadmin/phpmyadmin/commit/1204d23592a731e8bb1fa7e93ce5910522b1653a