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:

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 Fork me on GitHubgithub.