UPD: disable flatview in Stash

src/filesources/stash/ustashfilesource.pas

@@ -324,6 +324,7 @@ end;
 function TStashFileSource.GetProperties: TFileSourceProperties;
 begin
   Result:= _fileSystemFS.Properties;
+  Result-= [fspListFlatView];
   Result+= [fspLinksToLocalFiles, fspDontChangePath, fspDontCreateDirectory];
 end;
 

src/umaincommands.pas

@@ -1271,6 +1271,13 @@ begin
       AFileView.Reload;
     Exit;
   end;
+
+  if not (fspListFlatView in AFileSource.GetProperties) then
+  begin
+    msgWarning(rsMsgErrNotSupported);
+    Exit;
+  end;
+
   AFileList := TFileTree.Create;
   AFiles := AFileView.CloneSelectedFiles;
   for J := 0 to AFiles.Count - 1 do