Defines groups of character codes that should be selected together (considered a "word") when processing a double-click. Identical in use to the xterm resource of the same name.
The value consists of comma-separated groups of the form:
Each group specifies set of character codes in the range startchar through endchar should be treated as class. For example, in the default, the ranges 49-57 (characters 1 through 9), 65-90 (characters A through Z), 95 (_), 97-122 (a through z) and 216-255 (various ISO 8859-1 alphabetics) are part of class 48 (0). Any value not mentioned keeps its character code as its class.
A double-click selects adjacent positions on the screen that have the same character class.