[imp] "option" link lost

[li at elaboratio.com]

Hello,

I noticed today that the option link I enabled in the menu of Horde/IMP for all
users disappeared.
I changed nothing in Horde, the only thing I made was an upgrade of IMP, but as
this not resolved other problems I removed it again and restored the initial
situation. (Horde 3.0.2 and Imp 4.0.1)

I tried all settings playing with
* Should we display help links in the menu?  	
* Should we display options links in the menu? 	
* Should we display problem reporting links in the menu?

help and problem report links are or are in the menu according to what I set.
only the "option" option does not work and I *have* 
$conf['menu']['links']['help'] = 'all';
$conf['menu']['links']['options'] = 'all';

in my conf.php

I have no idea how this happened and where to look for.
Thank you for help.