Dimensions in pixels and retina/HiDPI

I am now playing around with ListBox and while I was hoping for a column width by characters, like a field (didn’t see it in the commands reference) you can choose pixels or relative sizes. This is no problem but I was wondering, if you set the project to be retina aware (Supports Hi-DPI = On), would it scale any elements that are set by their pixel count? Meaning simply, if I make a column width 100 pixels for use on a typical 1920x1200 display, on a retina or HiDPI display it is not going to still be 100px right? It would be scaled by however the macOS or Windows system retina/HiDPI is scaled? Or is support Hi-DPI not really ‘set it and forget it’ for these types of basic elements.

I read through http://developer.xojo.com/hidpi-support and there was lots of good info, but for a noob, difficult to follow since many of these elements they are talking about I have no experience with (weren’t covered in depth in the textbook).

The width in this case would actually be points. On a 1x, non-HiDPI screen that would be 100 pixels. on a 2x HiDPI screen that will be 200 pixels. So yes, it is basically set it to the size you want and don’t worry about specific pixels.