If was hiding (ie. collapsing blocks inside the code as well). Jetbrains (possibly a plug-in - focus on task els.) have a very-poor-man's version which hides a

If was hiding (ie. collapsing blocks inside the code as well). Jetbrains (possibly a plug-in - focus on task els.) have a very-poor-man's version which hides all files from the filetree except the ones opened in an editor. I never tried the issue integration out myself but agree that it's a good idea.