DiffGutterOperation (@NotNull Side side) { return createOperation(side, (ctrlPressed, shiftPressed, altPressed) -> { boolean isOtherEditable = myViewer.isEditable(side.other()); boolean isAppendable = myChange.getDiffType() == TextDiffType.MODIFIED; if (isOtherEditable) { if (ctrlPressed && isAppendable) { return createAppendRenderer(side); } else { return createApplyRenderer(side); } } return null; }); }