title: How to change only font size for the whole styled text in NSTextView
body: <p>I need to set a text size (for example to 42) of the selected rich text which uses multiple fonts. </p>
  
  <p>I imagine I can check attributes of each group of characters, modify the font size and set attributes back, but looking at the floating Font panel it seems like there should be a very easy and straightforward way to accomplish that. Do I miss something obvious?</p>