I find the sample pane to do a poor job at providing a realistic paragraph/block of text preview and I’m having a very hard time to evaluate the quality of a font for a block of text usage with it.
Here are 2 suggestion that would make a great difference:
Allow us to specify margin/padding for the pane text (I mean, come on even the pane label has more padding than the pane text)
Allow us to specify a line height for the pane text
This might make it in the next upcoming major release. If it all works, we will add a margin of 4 pixels to the left and right. There is no way to add a top margin afaik.