Thread:Project:Support desk/Vector Skin: Tabs/reply

This can simply be done with CSS. Vector is setting a background-image for div.vectorTabs span. This background image contains these blue lines, which are fading out towards the top. So this is what you have to change.

You can for example upload your own background image with dimensions 1x46px and set up according CSS rules in the wiki page MediaWiki:Vector inside your wiki to use it.