Improve Choose Font dialog
Some feedback from my OCD.
"Use Default" checkbox << can be interpreted as "Use as Default" in a quick look, I feel a more appropriated word would be "Restore defaults". Better yet, if I were building that GUI, I would put a Restore button bellow "Font weight" box with live action (restore visible form to default values).
The titlebar could be more contextual, in other words, if you are editing Menubar (eg. from right click menu), then display something like "Choose font - menubar".
The Sample box could be somehow editable by the user, good to check if the font supports some specific Unicode char (may be waste of time though, since Buffer area uses another font rendering).
Since now you can detect programmatically when form options changed (confirm?!), then make Apply button disabled until some change is done.
Nothing important, just sharing my thoughts for the records.