bug #4198 Hovering over pie chart gives fatal JS error

Signed-off-by: Madhura Jayaratne <madhura.cj@gmail.com>
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Merge remote-tracking branch 'origin/QA_4_1' into QA_4_1
Feature#1478 Make Column Headings Sticky

Signed-off-by: Atul Pratap Singh <atulpratapsingh05@gmail.com>
Add some docblocks

Signed-off-by: Atul Pratap Singh <atulpratapsingh05@gmail.com>
adjust sticky columns on nav width resize

Signed-off-by: Atul Pratap Singh <atulpratapsingh05@gmail.com>