improve border styling, required to refactor scrolling.

There is still an issue at the top-right corner:
the width has floating point pixels which are rounded differently
per browser and for table-display (header) and block-display (body).

The problem is still visible in chrome with certain window widths but
is reduced to only be visible in some pixels in the corner.
disable favorites component when feature disabled.
remove tab hover effect when feature is disabled.
add helptext for favorites.
IE layout optimizations.