Thanks, Max! Here's what I changed/fixed:

• moved some classes to their own files
• fixed a problem when loading the preset JSON: In a few cases, you were trying to load a List<SomeDartType>, but JSON only works with strings, numbers, bools, or lists/maps of those. So in cases where you want, say a List<ViewPreset> from JSON, I manually looped over the list of smaller JSONs and passed each one to ViewPreset.fromJson, and built a list that way. With a list comprehension, if you're familiar.
• In some cases, you were using FilesService.writeSettings directly. That does work, but it only changes your files on disk -- it does not alert Flutter that something has changed. So I switched all those calls to SettingsModel.update instead, and told the sidebar to listen for those changes.
• There was a little clippy warning in the corner if the presets, or any other setting, fail to load. That's because in release mode we simply override any corrupt settings with the defaults. I changed it so that in debug mode it throws a full-on error and does not wipe your settings.
• Instead of loading a preset via a dialog, I added all the presets themselves to the ExpansionTile. Clicking on one will load it automatically, and clicking the little delete icon will delete it. The delete dialog still appears, but it no longer asks you to choose a preset since you had to click the delete icon next to the preset.
• The old version of flutter_resizable_container was giving some issues with precision (eg, ratios adding to 0.9999999 and not 1.0). Upgrading from 0.4.2 to 3.0.0 helped, and after a little reconfiguring, introduced no further bugs

The errors were pretty subtle, so don't worry about not catching them in the code, but maybe a bit more testing could have caught them (eg, restart to find none of the presets are loaded). Anyway, it's ready to merge now, just figured I'd let you press the green button.

Approving after upgrading the resizable container package

Added an option to re-order your presets so users can organize them as they wish