After having round about 75 different thought types defined, I decided to create a separate empty brain only with these thought types as a basic brain for starting new brains and created a brainzip of this brain.
Creating a new brain by unzipping the Brainzip-File. At the home-thought the thought-type selector displays all thought-types with their original icons.
Now I rename the brain "File-Rename Brain". After this the thought-type selector displays only a few thought-type icons, many of them got lost.
As a workaround I create a new brain from the scratch, open the thought-type brain, selecting all thougth types, copy the thoughts, reopen my new brain and paste the thoughts(types) into it. In this case the thought-type selector shows all thought-types with their original icons.
Using Windows 7 / Java Version 1.6.0_29 / PB Version 126.96.36.199
Hope you can fix this issue in PB6 / PB7.