I noticed severe lag when selecting text first in ecrire. Which I was then able to replicate in edi. When selecting text in the following document F2779239 only 228K. Not a large file. Just save that and/or open it with ecire and/or edi.
edi /tmp/entrance_session.log
This is not the case in other stuff, and selecting follows the cursor without lag. Just like when selecting text in any EFL application or E.