Hi Francois,
this is an image of my raw data. here the epochs are automatically set in1 second but I intended to set them in 500 ms. I think according to this preset by the software, there is no possibility to have -200 ms in epochs.
and here as you can see, when I want to set the epochs, the epoch time section is locked and cant be changed.( it happens when I choose my events)
by importing the data, I have epochs in 1 second (0-1000 ms post stimulus).
is my explanation enough? if not, I should send you my raw data in EDF format.
Best
Shadi