[Paragraph spacing in text boxes]

I'm a new user to Affinity Designer and while there are some features that I like, it seems like the software has a mind of its own occasionally. 

I've been struggling to figure out the paragraph spacing between lines of text in text boxes. Most of the time, I'm able to select the text box or the text within and easily change the spacing between the lines so that it's not too cramped, but some of the time the text in the box is just completely unresponsive to changes in paragraph spacing. The only workaround I've figured out is that I can type into Word first and then paste into affinity and I usually don't have the same spacing issues. I had another situation where the text in the box was grey, but for some reason was registering as black, and there was nothing I could do to change it to black except copy the text into another text box where the text was black. 

I get that this program isn't necessarily created for writing a lot of text, but I'm frustrated that I can't accomplish incredibly simple tasks and I'm wasting tons of time trying to figure out how to resolve these issues. Does anyone have any ideas about what might be causing the text in boxes to do this. I'm using MacOS High Sierra, if that helps. Thanks.