backspace not delete well

[agentm]

HI!
when i erase lines using backspace as i always did, the marker (the vertical line | ) get "stuck" at the beginning of the line and not going up to erase the next paragraph. only if i press "del" it jump to the former (the one above the line which the marker is) and i can again press backspace and erase the next paragraph. is there some preotection that prevents it?? what is it??
how can i fix it?


thanks a lot!!