Selects objects within a complex or irregular region with a single mouse action.

(Lasso Selection Region), on the Selection Region flyoutYou can use Lasso to select either objects that are completely within the selection region (window method), or objects that are either within or touched by the selection shape (crossing method). Toggle between the window and crossing selection methods by using the Window/Crossing toggle on the main toolbar.
Ctrl while specifying a region, the affected objects are added to the current selection. Conversely, if you hold down Alt while specifying a region, the affected objects are removed from the current selection.To select using a lasso:
Click
(Lasso Selection Region).
Drag to draw a shape around the objects that should be selected, then release the mouse button.