Thread:Extension talk:Header Tabs/Header Tabs displayed as bulleted list in mediawiki 1.23

Hi i have recently migrated mediawiki to v1.23. But the problem is, in forms the header tabs are displayed as bullet list (having hyperlink to each section). My preference settings are set to default and i can see the installed version of HeaderTabs in Version page.

Although on my development box i have same version of mediawiki and HeaderTabs (only difference is in version of php, MySql and few other extension), it works perfectly fine.

Currently i'm using HeaderTabs v1.0.1 and have tried various other versions like v0.9, 0.10, 0.1.0. but it's still not working. I have no clue what to do further. Can you please help.