My friends! Unbelievible!
I can't create an exact parallel line with your tools! I used the option "Create parallel line!" but... after moving this "parallel line" the degree of the line became another that original! For what I have to pay so big money!? For your unparallel lines? Or may be I pressed the wrong button? May be you clarify to me how to create an exact parllel line!

Add a trendline, double-click on it, choose "Snap endpoints to price". Create a parallel trendline, its snap option will be enabled too. Now, grab the 2nd line by the red handle and drag it towards the 1st one until its endpoints would snap to the price. Can see only one line. Voila. This is purely to demonstrate that Wealth-Lab isn't to blame here, when the pointing device (i.e. mouse) is left out of the equation.

QUOTE:
For what I have to pay so big money!? For your unparallel lines?

Please consider adjusting the tone of your future replies to a more friendly. We've made an advance and extended your trial for another round, but nobody is holding a gun at anybody's head, urging to purchase the product. Thank you in advance.

If you create parallel lines in a linear scale and then switch to semi-log, you should not expect the lines to be parallel anymore.

On the other hand, a parallel drawn on a semi-log chart appears to have a small discrepancy that could be due to the points selected for the line when it is offset (so that you can distinguish it from the original line). In any case, I'd appreciate it if you created a Support Ticket for this issue and attached an image for it to see if we're talking about the same thing.