Currently Tux Paint doesn't have support for platform-specific system file dialogs, like "Open", "Save" and "Save As". Instead, it has an interesting built-in thumbnail-based sandbox for files, that shows the files in a specific directory for each platform. But some people and schools requested support for system file dialogs, so it's the main goal of this project.

A secondary goal is to integrate thumbnail dialogs into one codebase, since the functions are strictly related and have a lot of common code.