With Plasma 5 the document tabs in Kate have almost no border. Makes it hard to see (check the tabs in firefox or even konsole for example of good border design). Can we get Kate Themes or something so that these kinds of things can be tweaked. Everyone has different ideas on what they like visually so allowing a fully configurable theme would satisfy those variables
Even better would be to make it match the global theme (which you can change) by using a standard tab widget. See Bug 385520. *** This bug has been marked as a duplicate of bug 385520 ***