Creative

I'm wondering if your referring to a bug. I've found that "cmd" & "-" always seems to zoom out. "cmd" & "+" seems to zoom in just fine but sometimes it gets broken. You can either restart affinity and it seems to reset it, or you can use "cmd" & "shift" & "+" to zoom in while, "cmd" & "-" is used to zoom out. I hope that helps if that's what you're experiencing. I should post this on the bugs section of the forum though.

Is there a quick key to use? Is there something I can press while drawing a shape so that it would not follow the curve of the previous point but just make a straight line? (like pressing alt in sketch)

I think that would be describes as "text on path" and is on the list of things they aim to incorporate in the future