When you select text in Word or PowerPoint using the mouse, once you drag beyond the beginning or end of the first word, the selection starts to extend by a complete word at a time (rather than by a character at a time). For many tasks, this can be a handy feature. However, some users do not want this behavior.
To configure Word or PowerPoint so that selections begin and end precisely where you drag instead of observing word boundaries, click File to open Backstage view, click Options, and then click Advanced.
Under Editing options, clear When Selecting, Automatically Select Entire Word.