A graphical user interface (GUI) displayed at a user interface device includes a character string that includes a substring. The computing device detects a movement of an input object from a first location on the user interface device to a second location on the user interface device. The first location corresponds to a second handle element and the second location corresponds to a particular position in the character string that is not at a beginning or end of the substring. In response, the computing device modifies the GUI such that the second handle element is located at the second location. The computing device also determines whether to select all characters of the substring. All characters of each substring completely displayed between a first handle element and the second handle element are also selected. The selected characters are visually differentiated from the non-selected characters.