[Eeglablist] Can't use breakpoints in EEGLAB?

[Dr James K. Kroger]

Hello Arno et al., I want to write some plugins and am trying to trace 
through EEGLAB operation. I opened eeglab.m, pop_eegthresh.m, and 
eegthresh.m in the matlab debugger. I set breakpoints in eegthresh.m. 
Then I ran eeglab.m. The breakpoints (red dots) in eegthresh.m 
disappeared as soon as the execution began. When the blue eeglab 
interface came up, I loaded some data, then again set the breakpoints 
in eegthresh.m. When I executed the menu item reject data epochs/reject 
extreme values, the breakpoints again disappeared. Thus I can not watch 
the data structure at 

sweeps = size(signal(1,:),2)/pnts;
signal = reshape(signal(electrodes,:), size(electrodes(:),1), pnts, 
sweeps);

I want to do this so I can understand how the data is structured in 
your code so I can step through it similarly. You seem not to use the 
epoch structure (from epoching the data) and I'm confused about how you 
are working with the data. The tutorial steps through epoching the data 
for cleaning and some analyses but the code seems not to use the 
epochs. I may address this in a separate question.

I know using "clear" will also erase breakpoints and I see it in 
eeglab.m,  but I didn't see it in pop_eegthresh.m or eegthresh.m so 
don't see how that could explain the second erasure of breakpoints. If 
you have any clue to why this is happening or how to  step throught the 
code with the debugger,  it would be greatly appreciated.

Jim