I wrote this up for someone at work, but figured it might be useful to others. Here is the process I use to get hardware detected in Simplicity Studio. This procedure works-for-me as of v3.0 under Windows 7. YMMV for other versions, but it looks like the hardware detection works the same (i.e. just as problematic) in "v3.3" released a few days ago. Which, just to confuse you more, also reports as simply "v3". Any installed older "v3" version (at least 3.0, per my experience) will not show any updates or indication that a newer version exists.
On the left, press "Refresh detected hardware" and wait a while for your plugged-in kit to appear under 'Detected Hardware'. (Probably worth doing even if your hardware appears to already be listed.)
Note, if the target board or programmer ever loses power (or has a power glitch), some or all of this procedure has to be repeated. Likewise, if you begin receiving error messages like "SWO can only be used with target interface SWD" when trying to program/debug (whether your project uses SWO or not), try rebooting and redoing this procedure.
Hope this helps! (Also, somebody please fix this!)