Cannot draw right straight line in Visio 2013

Hello Expert
Sometimes I am trying to draw a right straight line horizon or vertical, but I cannot do that. The line that I draw is not right straight line, please see the screenshot in attachment where line a is not right straight line, and line b is a right straight line. I hope to draw line like line b.  It looks like the board on visio does not have enough resolution. How to resolve the issue ? Any one can give me some suggestion ?
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Scott HelmersVisio Consultant, Trainer, Author, and DeveloperCommented:
Hold down the shift key as you draw the line,  The shift key tells Visio to restrict the angle of the line to a multiple of 45 degrees.

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eemoonAuthor Commented:
Thank you. It can work in most cases
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