Integration of Tabbles with Windows Explorer is finally working. Now you can categorize files by right-clicking in Explorer. Here is a demo video:

There is much more that could be done with regards to Explorer integration (e.g. we could add a column in Explorer showing, for each file, the tabbles to which it is attached), but this first feature is by far the most useful.
Before I can release a version with Explorer integration, I will have to work a bit on the installer (which needs to be able to install and uninstall the Explorer plugin, aka shell extension).