fix(): zoom out tooltip fix, fixes #4729

public/app/features/dashboard/timepicker/timepicker.html

@@ -3,7 +3,7 @@
 	<li class="dashnav-move-timeframe gf-timepicker-time-control" bs-tooltip="'Shift time backward <br> (left arrow key)'" data-placement="bottom">
 		<a ng-click='ctrl.move(-1)'><i class="fa fa-chevron-left"></i></a>
 	</li>
-	<li class="dashnav-zoom-out gf-timepicker-time-control" bs-tooltip="'Time range zoom in <br> CTRL+Z'" data-placement="bottom">
+	<li class="dashnav-zoom-out gf-timepicker-time-control" bs-tooltip="'Time range zoom out <br> CTRL+Z'" data-placement="bottom">
 		<a ng-click='ctrl.zoom(2)'>Zoom Out</a></li>
 	</li>
 	<li class="dashnav-move-timeframe gf-timepicker-time-control" bs-tooltip="'Shift time forward <br> (right arrow key)'" data-placement="bottom">

public/app/features/dashboard/timepicker/timepicker.ts

@@ -92,7 +92,7 @@ export class TimePickerCtrl {
   move(direction) {
     var range = this.timeSrv.timeRange();
 
-    var timespan = (range.to.valueOf() - range.from.valueOf());
+    var timespan = (range.to.valueOf() - range.from.valueOf()) / 2;
     var to, from;
     if (direction === -1) {
       to = range.to.valueOf() - timespan;