Directory tree is missing something for adding new projects

[Akuli]

I think there's a few options:

• An entry where you can type the name of a file or directory to open it, with decent auto-completions
• A button that opens a gui dialog for opening file or directory (not great because there's already File --> Open?)
• Both

[Akuli]

If I add the entry, it could also act as "Type to filter", similarly to plugin manager