[Saga[_2_]]

Hello all. Sometime Ihave the need to include special characters,
such a vowel with an accent. I do this by pressing Alt key and
typing in ASCII using the numeric keypad. The problem is that
sometimes I miss a key or a number and the special character
does not display, but the vertical bar cursor changes in that
a small triangula flag pointing left appears at the top of the text
cursor. I have tried to duplicate this behavior unsuccessfully.
Does anyone know what this text cursor indicates and why the
flow and control of text behaves in a different way?

By "different way" I mean that I place the text cursor at a
specific location and when I start typing, the text appears else
where, or when I try to move the text cursor using the arrow keys
the cursor moves to an unexpected location. Thanks. Saga