How to fix code folding in monodevelop

Hi there.
In monodevelop there is a feature called code folding but sometimes it just doesnt work, the little plus/minus signs are missing from the margin. Does anyone know how to “fix” the code parsing or whatever it is thats causing code folding to disappear? I code in js.



Here you can see, the OnEnable function is fine, but AssignNextItem() which is the last function in the script does not display these. The script compiles without errors