Please refresh your Galaxy session by using the commands "ctl+shift+r". This will reload the user interface and the tool should be available. Note that this is an updated version of the tool form. If you should run into issues while using it, please submit a bug report.
This advice applies to any other tools that may seem to be behaving strangely in Main. One refresh will correct all.
Thanks all for your patience, Jen, Galaxy team
I'm having the same issue on a local instance of Galaxy
I updated Galaxy by running hg pull -u but this did not solve the issue.
Any other ideas ?