- I use left exponent a lot with the transpose symbol for matrices. I would have supposed it to work like this :

hit the matrix name, say A, then Ctrl-L ^, then the symbol such as t for the transposition. Instead, I get the exponent to the right of A when I proceed like this. Second try : I enter the name of the matrix, then selects it with shift-left, then hit ctrl-L ^ and A gets transformed into a left exponent. So I learned that instead you put the left exponent, then the matrix and everything is good. Actually I encoutered a situation when going out of the exponent put me out of formula editing, but I can't reproduce it. If I encounter it again, I'll post here.

- when writing a big sum with indices directly under and over, which is automatic when big centered formulas, it is a bit weird to have to hit twice the right key for the focus to go back to "normal" or maybe I should say that what is weird is what happens if you don't ! Not a big issue of course, the cursor being a good hint of what the focus is, but still something uncanny for newcomers when you go from :

<Capture d’écran 2021-06-27 à 09.42.44.png>

to

<Capture d’écran 2021-06-27 à 09.42.52.png>

just hitting a.

- Something I didn't understand, but by writing this mail and experimenting at the same time, I think I just did... Sometimes I want to write the product |x| |y| with no multiplication symbol, just the space that TeXmacs puts automatically by hitting * with no alternate version. In that case, TeXmacs only enters the left part of the absolute part when I hit the | symbol, whereas usually it gives me both. I am pretty sure now it is by design, as it allows to obtain quickly the semidirect product symbol as an alternate, which makes sense, but still something to get accustomed to.