Double-clicking with mouse button 1 and double-tapping — its pen equivalent — is a shortcut for the default operation of an object. In text contexts, it is commonly assigned as a shortcut to select a word. When supporting this shortcut, select the word and the space following the word, but not the punctuation marks.
Note
Double-clicking as a shortcut for selection only applies to text. In other contexts, it may perform other operations.
You can define additional selection shortcuts or techniques for specialized contexts. For example, selecting a column label may select the entire column. Because shortcuts cannot be generalized across the user interface, however, do not use them as the only way to perform a selection.