The following functions are available:
opening or closing the folder tree
changing the folder tree width
opening or selecting a folder in the folder tree
How to change the folder tree width:
Move the cursor to the right border of the folder tree. A double arrow will be displayed.
Drag the border to the left or to the right.
How to open a certain folder:
If the folder tree is closed, open it.
To view a folder's subfolders, click on the arrow next to the folder name.
To open a folder, click on it.