Drop button anchors easily broken by common theme styles [#2271341]

Problem/Motivation

Merely adding something like a background color to anchors breaks drop buttons when they are anchors, i.e. admin/structure/views where the Operation links are anchors.

This was highlighted by #890362: Links should not be indicated by color only, and Bartik set as admin, you get border bottom on every operation link and does not look great - that is OK IMO, they still work, however this is just a border bottom, the broader issue that these anchors can be rendered very ugly, if not potentially unusable, by common theme styles.

FWIW I have no idea what component to categorise this under, CSS seems the closest?

Proposed resolution

Discuss: either isolate drop button styles which is probably too much specificity or verbose declaration blocks, or suck it up and themes have to deal with it, i.e. too bad for you. I have few opinions on this but probably lean to the latter - too bad for you and we preserve the low'ish specificity of the current selectors.

For example I already wildly restyle these in my base theme and really the last thing I want is to have to plaster ID's all over the show, I don't really want a specificity war to break out every time I need to style a drop button. I personally would rather deal with it myself in my theme.