Have you looked at the source?
- TForm1.DoExecute
- TForm1.DoSearchPosition
Both have comments when they get executed. You can debug them to see what they do.
In both of them, in the nested procedure ADD, change the condition to:
if pos(UpperCase(SynCompletion1.CurrentString),UpperCase(s)) > 0 then
SynCompletion1.ItemList.Add(s);
In DoSearchPosition you can play with APosition if you want a different item selected => mind then you reset whatever the user did by up/down keys.
You can leave position unchanged. Or you can check which word is at that position, and then set APosition to the position to which that word moved.