# notebook scrolling problem in 10.2: worse than ever? how to fix?

I use Mma notebooks to present in the classroom, so for me this is a serious problem. Before starting a class, I close all the sections, subsections, and subsubsections. During a lecture, I open these and close them back down as I move through the notebook. I will be merrily moving through my notebook, when suddenly I can no longer scroll. (Both the scroll keys and the scroll bar stop working.) I have had this problem occasionally in past versions, but I seem to be seeing it more than every in 10.2. Is it worse, or have I just become unlucky?

I think the problem occurs most often when I open a closed subsection. I can sometimes fix the problem by reducing the notebook magnification. (My recollection is that reducing it to 100% used to be a nearly sure-fire fix, but this no longer seems to be the case; sometimes even lower magnifications do the trick.) Sometimes this change in magnification fixes things: I can even restore the magnification, and continue to scroll. Other times, I have to close the "offending" subsection, and if I am lucky, I can reopen it and continue to scroll. In the worst case, I cannot scroll with the subsection open, forcing me to either close Mma and reopen it (usually works) or skip prepared material. I would appreciate hints/clues for how to deal with this situation in real time when it arises.

• Try selecting the cell bracket and use the arrow keys. Or delete graphics output (from Plot3D etc) that you don't need anymore. I've only noticed it on notebooks that are fairly large. If they are large notebooks, consider dividing your lecture into several notebooks. It hasn't seemed worse in 10.2. My guess is that large amounts of data hidden in cells (e.g. graphics) confuses the mechanism that predicts how a scrollbar position maps to a file position. (That's an uninformed wild guess, though.) – Michael E2 Sep 2 '15 at 23:14
• Can you record a screenshot gif of the behavior? – M.R. Sep 3 '15 at 2:27
• I have also seen this in version 10.1 on Mac OS X, in a notebook with several hundred cells, even though it contained only a few images (total size less than 20MB). I was able to get it "unstuck" by trial and error, but don't have enough data points to know what's really going on. It could be the combination of large cell count and some large images. So instead of being worse in later versions, maybe it's just worse because your notebook has grown larger. Anyway, I'm just guessing, but agree that there is an issue. Could you add what OS you're using? – Jens Sep 3 '15 at 5:07
• I have also been annoyed by this problem for a long time in all my Versions (5.2/8.0/10.1) There are two things I try: 1) reduce the size of the display (Strg+Mousewheel back in Windows) 2) shift the scroll bar on the right hand side. Here some patience is required in waiting for a reaction, but I have observed that once there was a reaction also the other scrolling mechanisms work. – Dr. Wolfgang Hintze Sep 3 '15 at 11:29
• Try turning off the Predictive interface – David Creech Sep 3 '15 at 13:05