To Select Multiple Targets

From the tree of the Level Manager (or Level Display) dialog, press and hold down the left mouse button on the first file to be selected.
Drag the cursor over any addition files to be included in the selection.
Release the left mouse button.
The selected files are highlighted in the tree and all levels in those files appear in the level list.

Note: Any changes made to a level in the level list affects all the selected files in the tree if MS_LEVEL_EDIT_NESTED_ATTACHMENT_LEVELS is set to 1. If not set to 1, changes to the nested levels are not written.