Select Elements
- Click a shape or connector to select it. 
- Click an element while holding down the Shift key to toggle the element's selected state. 
Select Multiple Elements
To select multiple elements do one of the following.
- Click elements while holding down the Shift key.
- Drag a mouse over elements while holding down the left mouse button. Elements that are inside or cross the selection area, will be selected.

Select All
Press Ctrl+A to select all elements in the document.