When FrameMaker creates Acrobat links from cross-references and regular hypertext markers, it sets their properties rectangle location and dimensions, border style ( = none), border color ( = invisible) and highlight style ( = invert). TimeSavers/VisLinks (Link Controller) lets you control all these settings globally: line style (continuous/dash), line color and highlighting style (Inset, Outline or None).
Using TimeSavers' Link controls (Links/General tab), you can automatically specify all the visual properties of links available in Acrobat. Aspects that can be controlled include box/line color (internal/external links can optionally have different colors), line width, baseline offset, link highlight style.
When displayed in Acrobat/Reader 6 or higher, the link can be shown with an underline -- visible on-screen but not printed. This improves the display (as this underline property is displayed with a consistent line thickness), and also prevents cluttering the paper output.
With SideLinks (TimeSavers + Navigation Assistant), active cross-references can be automatically marked with a user-defined symbol, placed in the margin or within the text, reducing the visual "noise" associated with numerous colored/underlined text links.
With TimeSavers + Forms Assistant, custom links ("buttons") can have additional interactive styles.