Sorry, new bug introduced by "Fixed bug where "Stop All" would not appear when adding or removing sources from a search":
1) select 1-n sources
2) search something
3) wait for the search to stop
4) click search again
= bug: "stop all" appears although nothing is searched (because there was no change to the artist/album fields, nor to the limits).. also clicking that link doesn't do anything for obvious reasons.