Don't reload FX when undoing certain SWS actions

Issue was reported here: http://forum.cockos.com/showthread.php?p=1438393#post1438393
I didn't fix any of S&M actions since I presume Jeffos knows best what to fix. Jeffos, if you don't have the time to recheck your stuff, just ping me and I'll give it a go
Fixes to last commit (6ee50d4f514b7c0ecacac978b41d2ea08758d73d)