Forti Converter v5.4.0 Build0345 : cannot tune / edit policy

Hi,

Using the new FC 5.4, I converted a Cisco FWSM rulebase

to FG 5.4. several times using different interface mappings and route files.

The results of the new converter GUI look promising.

While tuning, I can edit interfaces, firewall addresses, services, addr. & srv. groups, routes etc.

But I can not edit rules of the firewall policies. When double-clicking on a policy, nothing happens..

Tried recent Firefox, Chrome as well as IE & Edge, disabled popup blocker, cleared browser cache...

Interestingly I was able to edit policies on the very first conversion result !

Any hint ?

BR,

Frank