ListGrid: removing all columns in MultiSortDialog leads to JS error

[mikalai]

Hi,

When MultiSortDialog is displayed, the following steps lead to JS error:
- Using the menu remove checks near Column and Order column names --> Column and Order column disappears from the dialog
- Click Add Level button now --> Script error appears

See details below:
SmartClient Version: SC_SNAPSHOT-2011-12-05/LGPL Development Only (built 2011-12-05)

Browser - IE9

12:30:24.414:MUP6:WARN:Log:Error:
'Unable to get value of the property 'valueMap': object is null or undefined'
in http://localhost:8080/knowledgecentral/contentmanager/sc/modules/ISC_Containers.js
at line 399
crashed in: MultiSortPanel.addLevel()

[Isomorphic]

Please try a more recent version, and an up-to-date patched build.