The menu item Drives->Multiple Trees toggles the Multiple Trees option, which enables/disables the addition of trees to the Directories window without the necessity of holding down the Ctrl key.
The default submenu item is either Enable or Disable, depending on the current state. When in the enabled state, the Directories window is not cleared before reading a different drive, thereby adding a directory tree for each drive read.
Cascaded submenu options allow you to load all drives, restore the last used multiple drive setup or restore the last used multiple drive setup upon startup.
Non-Persistent Multiple Trees
As an alternative to enabling Multiple Trees when more that a single tree is desired in the Directories window, holding down the Ctrl key and double clicking a drive letter will add that drive temporarily to the tree. It will persist until the next drive read without the Ctrl key down. It is possible to add other drive trees by repeating this action.
Advantages and Disadvantages
The advantages of multiple trees is that you may rapidly switch between drives that have been previously read with a single click on the drive letter. The only refresh that is required is to reread the current directory for the selected drive. Implemented in this fashion, only those drives used are ever read, and those only once. Also, file operations across drives is much easier with the Point and Click interface. You may also drag and drop files or directories from a Files window to any directory of any drive in the Directories window.
The disadvantages of multiple trees is that you can end up with a lot of directories in the multiple trees and more scrolling is generally required. However, the current directory for a drive is automatically selected when a drive switch is made. Also more memory is required. Because of the latter, if you have several drives you should consider how many are in memory and remove those that are no longer needed. The number of trees is not important; what consumes memory is the number of directories in those trees.
Accelerator Keys - Ctrl T