Help fix

`HelpView.render` method fails because `offset` is undefined. And Flood doesn't continue to execute a code after the exception. That's why switching between tabs doesn't work.

Probably the issue with tabs was meant here [REACH-97 Opening dyf file causes home workspace to disappear - should simply focus custom node](http://adsk-oss.myjetbrains.com/youtrack/issue/REACH-97)