21. The method of claim 17, further comprising: when the current selection is the selection of the computational construct representing the binary operator and its operands in the left selection mode and the user inputs the second indicator, setting the current selection to a selection of a parent computational construct of the binary operator by applying the second indicator to the parent computational construct.
21. The method of claim 17, further comprising: when the current selection is the selection of the computational construct representing the binary operator and its operands in the left selection mode and the user inputs the second indicator, setting the current selection to a selection of a parent computational construct of the binary operator by applying the second indicator to the parent computational construct. 22. The method of claim 21 wherein the first indicator is a tab and the second indicator is a shift-tab.