Just click on a line to display the pane or view its children.
You can use the keyboard's arrows to navigate in the tree.
To enable the keyboard navigation, just click on a line and:
- Use ↑ and ↓ to go to the previous or the next line.
- Use → to display pane or view children of the current line.
- Use ← to go back to the previous column.
You can type a letter to select the first line which begin with this letter.
For example, type L
to select the line Luc
if it is in the current column.
You can resize column with the mouse, just drag and drop its rigth border.
You can click on the path to navigate in columns.
Code is available on 
github.