hi.. i'm having some problem here.. it seems like i cannot use the straiht line anymore.. everytime i wanna do straight lines the problem comes out like this..

This is a weird problem..if all else fails..

Go to Edit > Preferences > General

Click Reset All Warning Dialog

i assume u attached an arrowhead



check here to confirm it

Is this because of the arrow head or is it because you can't draw vertical or horizontal line. Need to check your mouse too if you cannot draw horizontal line. Try press shift and draw to get a perfect straight.