text: iD.ui.UndoRedo = function(context) {
      var commands = [{
          id: 'undo',
          cmd: iD.ui.cmd('⌘Z'),
          action: function() { if (!saving()) context.undo(); },
          annotation: function() { return context.history().undoAnnotation(); }
      }, {
          id: 'redo',
          cmd: iD.ui.cmd('⌘⇧Z'),
          action: function() { if (!saving()) context.redo(); },
          annotation: function() { return context.history().redoAnnotation(); }
      }];
  
      function saving() {
          return context.mode().id === 'save';
      }
  
      return function(selection) {
          var tooltip = bootstrap.tooltip()
              .placement('left')
              .html(true)
              .title(function (d) {
                  return iD.ui.tooltipHtml(d.annotation() ?
                      t(d.id + '.tooltip', {action: d.annotation()}) :
                      t(d.id + '.nothing'), d.cmd);
              });
  
          var buttons = selection.selectAll('.undo-redo')
              .data(commands)
              .enter().append('button')
              .attr('class', 'disabled undo-redo')
              .on('click', function(d) { return d.action(); })
              .call(tooltip);
  
          buttons.append('span')
              .attr('class', function(d) { return 'icon ' + d.id; });
  
          var keybinding = d3.keybinding('undo')
              .on(commands[0].cmd, function() { d3.event.preventDefault(); commands[0].action(); })
              .on(commands[1].cmd, function() { d3.event.preventDefault(); commands[1].action(); });
  
          d3.select(document)
              .call(keybinding);
  
          context.history()
              .on('change.undo_redo', update);
  
          context
              .on('enter.undo_redo', update);
  
          function update() {
              buttons
                  .property('disabled', saving())
                  .classed('disabled', function(d) { return !d.annotation(); })
                  .each(function() {
                      var selection = d3.select(this);
                      if (selection.property('tooltipVisible')) {
                          selection.call(tooltip.show);
                      }
                  });
          }
      };
  };
  