Great plugin. I use it to run Spek spectral viewer on files (to tell fake lossless from real lossless), because fooCDtect gives dubious results more often than not.
However if the file is an image+cue sheet, playlist references the .cue file, so when you feed the path to Spek, it tries to open .cue file and expectedly fails. I wrote a little script to circumvent this.
D:\spek.exe "$if($and($stricmp($right(%path%,7),wav.cue),$stricmp($left(%__codec%,6),Monkey)),$left(%path%,$sub($len(%path%),7))ape,$if($and($stricmp($right(%path%,7),wav.cue),$stricmp(%__codec%,WavPack)),$left(%path%,$sub($len(%path%),6))wv,$if($and($stricmp($right(%path%,7),wav.cue),$stricmp(%__codec%,FLAC)),$left(%path%,$sub($len(%path%),7))flac,$if($stricmp($right(%path%,7),ape.cue),$left(%path%,$sub($len(%path%),7))ape,$if($stricmp($right(%path%,6),wv.cue),$left(%path%,$sub($len(%path%),6))wv,$if($stricmp($right(%path%,8),flac.cue),$left(%path%,$sub($len(%path%),8))flac,$if($and($stricmp($ext(%path%),cue),$stricmp(%__codec%,FLAC)),$left(%path%,$sub($len(%path%),3))flac,$if($and($stricmp($ext(%path%),cue),$stricmp(%__codec%,WavPack)),$left(%path%,$sub($len(%path%),3))wv,$if($and($stricmp($ext(%path%),cue),$stricmp($left(%__codec%,6),Monkey)),$left(%path%,$sub($len(%path%),3))ape,%path%)))))))))"
It relies on the .cue file being named either exactly the same as .flac, .ape, or .wv file, or be named the same and end with .wav.cue, .ape.cue, etc. This should cover most of the cases, but if there are differences in file names before extension, it will not work.
Hope someone finds this helpful.