CorelDRAW Graphics Suite X6 :: Change Width Of Text Box

I am new to CorelDRAW.  I am using it to generate scientific application notes that contain both graphics and text.  I am running into a problem where I have a negative number that is close to the end of a text line (using justified format).  CorelDRAW wants to treat the negative like a hyphen and keep the "-" on one line and then moves the number to the next line.  For example, if the phrase "...cooling to -150 C for 5 minutes..." were to wrap across a line, it would look like:

"...cooling to -

150 C for 5 minutes..."

Instead of:

"...cooling to

-150 C for 5 minutes..."

The only way I can figure out how to get past it is to change the width of the text box so the lines wrap in different places.  I have tried adding a space or two, adding hidden text (text with the same color as the background).