Found a setting in prorealtime that helps heaps. Right click on any trend line on a chart and choose Configure Trendline
Tick the box that says something like "Show timeframe on which trendline is drawn" and it labels the support and resistance lines accordingly. It makes a lot more sense now because sometimes it draws lines you can't attach to any on the daily chart (for example) but it might be a support line from the weekly chart and they don't always match up. Very very handy to know.
