Reproduced in Trunk (git commit d83c91ba7eb5f3a30ad4a3897f8dcd4f5749320c)
Steps to reproduce:
1. Start 6.1 GA2
2. Deploy attached portlet and place on a page.
3. There are 6 buttons with different java script syntax.
a. Both single and multi line comments work because syntax is correct.
b. Only multi line comments work.
c. Only multi line comments work.
All 3 scenarios work in 6.0.12 when core-2 fixpack is installed.
Installing core-2 in GA2 does not resolve the issue.