Why has my style changed the page layout when I only changed the font?
I am trying to use a Style so that my scores default to using a different font for the main headings, but other things have changed. I opened up an existing score of mine, went into Format, Style ..., Text Settings, where I happily changed the font. All good so far. However, I noticed the layout of the score changed. For example the page margin at the top shrunk. I checked in Format, Page Settings.... and that confirmed that the margins had all changed - the top margin had changed from 15mm to 10mm. Why did that happen when all I changed in the Style was the Heading and Composer text fonts?
Accepting that this had happened, I then looked for a Page setting within Format, Style... and sure enough there was one. However, it did not have a page margin setting within it. It does show "Music Top Margin" measured of "7.0sp". Is this the same as top page margin but using a different type of measurement system? In summary, why did the page margin change and how can I set it back as part of the Style?