I would like to change the behaviour of my "end" and "orig" key, i've been used to shortcuts like CTRL + right for END and CTRL + left for ORIG.
The thing is I've actually succeed to change my END key behaviour, by changing the SCI_LINEENDEXTEND shortcup in Scintilla commands menu, but I can't find the corresponding shortcup for LINESTART, could someone help me out on this ?
Although I'm not familiar with the "ORIG" term, I believe you want one of the "SCI_HOME" related commands. This section of the Scintilla documentation explains it pretty well. You will probably want the plain SCI_HOME command but there are different ones based on how you want to handle wordwrapping and whitespace, such as SCI_VCHOME, SCI_HOMEDISPLAY, and SCI_VCHOMEDISPLAY
Hope this helps :)
Edit: Also keep in mind that each of the commands I mentioned have the "EXTEND" version such as SCI_HOMEEXTEND.
This totally helps, I too wasn't familiar with the "HOME" term, tank you a lot ! :)