I do kind of agree with Tom a little here, viewports are part of the fundamental features of VW and you would have though that there would have been a button or shortcut already there out of the box, but on the other hand, when i first started using VW many many years ago, the very first thing that frustrated me was shortcuts that were different to other bits of software i was used to, so i changed them all, its dead easy and makes you work more efficiently....... if you are not using shortcuts for everyday tools, commands etc then you are not maximising you time!