wawachief
commented
4 years ago If assigning different behaviours to the same event depending on the context is tricky, a suggestion would be to assign the '-' character to another key and leave space with the opposite function. I tried this modification and it does the job : I have both the minus sign and the opposite function.
Thank you for taking into consideration the alpha+- key as '-' symbol in the edit line. That fixed the problem with minus sign in matrices but the opposite operator is gone. It would be great if the alpha+- had 2 behaviours : one during edition where it inserts '-' at the cursor's position, and one when nothing is edited where it takes the stack[0]'s opposite.