Opera shows the config fields for all of the repository browsers rather than
just the currently selected one.

This appears to be due to a JavaScript error:

message: Statement on line 664: Could not convert undefined or null to object
Backtrace:
Line 664 of linked script http://192.168.2.10:8080/static/bba22259/scripts/
hudson-behavior.js
td.style.display = show ? "" : "none";
Line 1 of script
updateDropDownList(this);
At unknown location