diff --git a/gradint-build/src/makeevent.py b/gradint-build/src/makeevent.py
index b7491b2f5c0cb8e57928800f5c579d8521bc13c6..93b24cb71dc11bcefbe98a439d048f159f89b4be 100644
--- a/gradint-build/src/makeevent.py
+++ b/gradint-build/src/makeevent.py
@@ -94,7 +94,7 @@ if synthCache:
     for i in synthCache_contents:
         if i.upper()==transTbl: # in case it's a different case
             transTbl=i ; break
-    synthCache_contents = list2set(synthCache_contents)
+    synthCache_contents = list2dict(synthCache_contents) # NOT 2set, as the GUI can delete things from it
     if riscos_sound: show_info("done\n")
 synthCache_transtbl = {}
 if synthCache and transTbl in synthCache_contents:
diff --git a/gradint-build/src/system.py b/gradint-build/src/system.py
index 056a5b3158d93804d6460278c113d548624be71b..7c2a96cd75ce5a8d9fdda0dc94741182d3291921 100644
--- a/gradint-build/src/system.py
+++ b/gradint-build/src/system.py
@@ -106,12 +106,12 @@ dotwav = extsep+"wav" ; dotmp3 = extsep+"mp3" ; dottxt = extsep+"txt"
 cwd_addSep = os.sep
 if os.getcwd()[-1]==os.sep: cwd_addSep = ""
 
+def list2dict(l):
+  d = {}
+  for i in l: d[i]=True
+  return d
 try: list2set = set
-except NameError:
-  def list2set(l):
-    d = {}
-    for i in l: d[i]=True
-    return d
+except NameError: list2set = list2dict
 
 # settings.txt and advanced.txt
 # (done here before the variables start to be used in