CopyEvaluate ButtonStyle
The fourth button in the sample palette has the "CopyEvaluate" ButtonStyle. If you select 15 in the next cell and press the fourth button, then a new input cell containing 16 (the result of 15+1) is inserted after the original input cell. The expression in the new input cell is selected once evaluation is finished. The results are similar if a part of an output cell is selected.
Created by Mathematica (May 16, 2004)