A recurring issue with students using IDLE is the user interface for the fonts and tabs preference settings.

* The default setting of 4 space tabs is a good default, but the giant slider cries out to be moved (usually when people are intending to increase their font size).  A slider was not a good choice.  It should use something like what is currently used for font size.

* On the other hand, the font size would benefit from have a slider.

* I don't know if anything can be done to improve the selection of the font face.  The scrolling menu of choices worked great back when we only had a handful of choices but it had grown problematic with a large number of choices.  It is a bit of a struggle to select Menlo on a Mac if you already know what you want.