How do you add to a selection when using the Lasso Tool?

Using the Lasso Tool in graphic design software, holding the Shift key allows you to add to your current selection. When you do this, any area you draw over will be included in the existing selection, effectively expanding it. This feature is essential when you want to refine your selection to include multiple areas or shapes that are not connected.

In contrast, the other options do not serve this purpose. The Alt key is typically used to subtract from an existing selection, while pressing Ctrl is often utilized for various functions such as duplicating or transforming objects, depending on the software. Double-clicking does not relate to modifying selections with the Lasso Tool. Understanding how to manipulate selections using modifier keys is crucial for effective editing in design software.