Options Panel
Clicking the down arrow will hide any players that are locked with no buffs shown. Buffs that expire will turn red, and if you have the spell you can click to recast.
Setting up, showing all buffs on players. Cast the buffs you want to monitor, then lock it down and remove the ones you don't want
Enabling 'Show only castable' will hide any buffs that you cannot cast. Enabling 'Show only buffs you cast' will further hide ones that weren't cast by you. Players that are locked will keep showing the buffs you locked to them.