Clear Filter should be in disabled style when no criteria are selected

Steps to Reproduce

1. visit http://localhost:8080/keikai.test/issue.zul?file=/book/colorFilter.xlsx
2. open the first column dropdown

Current Result

the "clear filter" looks enabled

Expected Result

It should look disabled

Workaround

.zscellpopup .zsafp-itemsdlg .zsafp-clear-disabled

{ color: #AAAAAA; }