add diagram of how tab borders are drawn.
add diagram of how tab borders are drawn.

pickettd/code-dot-org,ty-po/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,ty-po/code-dot-org,ty-po/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,ty-po/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,ty-po/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,ty-po/code-dot-org,ty-po/code-dot-org,pickettd/code-dot-org,ty-po/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org