Hi, Laura-

Wow, that is confusing, since the other menus open up fine. I am remotely logged into to a cluster here at NIH ("ssh -X ..."), and I can open the menus fine, including the Olay one.

Some thoughts:
+ The only time me rightclicking on Olay did nothing was if the volume had only 1 subbrick. In your case, I don't see how this would be a problem, though, because you have 150 subbricks.
+ Is it possible that the menu is opening up off screen (for what is being sent back to your Mac)? I wonder if that is an issue, because of how the large menu is being truncated.
+ I wasn't sure whether you mentioned trying opening AFNI on your Mac directly and if the same behavior applies (or if you had just ssh'ed from your Mac, without using noVNC). If you do try just opening a multibrick overlay on your Mac, does this happen? And what is the output of "afni_system_check.py -check_all" on your Mac?
+ I can also "shift+rightclick" on Olay and get the scrollbar menu-- does that work?
+ Finally, in the lefthand part of AFNI GUI is an "index" button-- you could type in the index that you want and hit Enter, and the olay should jump to that. If your ulay has only one brick, it will just stay there; the question of what happens with your Thr brick index depends on what you have set on your computer. You can set it to jump to that same index, or to jump to the Olay index+1, or to be "free" and independent-- that can be done through ~/.afnirc options (see below), or by the dreaded right-click on the "Index" button itself.

--pt

about relevant environment variables from here:
[afni.nimh.nih.gov]

-----------------------------
Variable: AFNI_SLAVE_FUNCTIME (editable)
-----------------------------
When the underlay and overlay datasets both are time-dependent,
switching the time index will change both the underlay and overlay
sub-bricks. If you want the time index control to change ONLY the
underlay sub-brick, then set this variable to NO.

----------------------------
Variable: AFNI_SLAVE_THROLAY
----------------------------
This variable allows you to control the INITIAL setting of the widgets
that slave (or not) the threshold index to the overlay index. (These
widgets are on the 'Index' right-click popup chooser and on the
threshold slider right-click popup menu.)  The values you can set for
this variable, and their effects, are listed below (not case
sensitive):
  'OLay'    *or*  '=='  *or*  '0'  ==> threshold index = overlay index
  'OLay+1'  *or*  '+1'  *or*  '1'  ==> threshold index = overlay index + 1
  ANYTHING ELSE                    ==> threshold index is free and wild
This variable replaces the 2 variables listed below. Again, this only
controls the INITIAL setting of the widgets -- you can change them in
the AFNI GUI later at any time. Setting this variable after AFNI
starts (e.g., from plugout_drive) will have little discernable effect.