The issue was fixed in Trac 1.0.2:
The relevant entry is:
Multiple forms submits are disallowed (#10138).
There is a problem with your installation. The browser console shows:
9390:73 Uncaught TypeError: $(...).disableSubmit is not a function
at HTMLDocument.<anonymous> (9390:73)
at o (jquery.js:2)
at Object.fireWith (jquery.js:2)
at Function.ready (jquery.js:2)
at HTMLDocument.B (jquery.js:2)
I suspect the static assets were not redeployed after upgrading Trac:
More details in this ticket:
Ryan