Table rendering breaks on subsequent runs

[ncautotest]

Description

Subsequent runs of scripts containing table{..} breaks the UI.

Steps to reproduce

1. Run the following groovy script:

table {
    columns('Path', 'Title', 'Status')
    rows([
            ['/', 'first', 'good'],
            ['/content', 'second', 'none']
        ])
}

2. Re-run the same script a second, third, fourth time...

Actual result

On subsequent runs extra column headers are added to the table:

NOTE: depending on the table shape the table might not be rendered at all unless the page is refreshed. Also combining table {} statements with println(...) intermittently results in the table not being displayed.