Microsoft Word 2016, 2013 and 2010 has feature using which you can drag and drop the text in a document. But if you do not want drag and drop then you can use Word Options to disable or turn off the feature. Listed below are the steps to turn off drag and drop of text in Word
Step 1: Click File menu then options link.
Step 2: In the Word Options window, click Advanced tab.
Step 3: In Advanced tab, scroll down to Editing Options then un mark text with label as Allow text to be dragged and dropped.
Thus un checking this option you can turn off the drag and drop of text in Word 2010.
Also See: Show or hide style pane in Word