You can select elements one at a time, drag a box over them to capture them, or select all using keyboard shortcuts.
Selecting All Elements
To select all of the elements in the model, click on the work area and use the Ctrl+A (Windows) or Command+A (Mac) keyboard shortcut. All elements (tasks, events, sequence flows, etc) will be selected. You can then apply whatever action you wish to the selected elements using the toolbar options.
Selecting Individual Elements
To select an individual element in the model, click on it. If you need to select several elements, hold down the SHIFT or CTRL keys whilst clicking on the required elements. Alternatively, keep the left mouse button pressed and drag your mouse over the elements that you want to select. The selection process will finish, when you release the mouse button.
When an element is selected, action icons are displayed next to it, which let you edit or delete it, or add a new element leading from it. The actions included in this toolbox are also available via the left-hand palette in the model editor.
To deselect any currently selected elements, click on an empty area of the work canvas.